Introduction to Kosher/Kashrut
Introduction to Kosher/Kashrut
The human soul can achieve its goals when the body's physical desires and abilities are channeled to do good. Since our bodies are meant to serve holy purposes, what goes into them (as food) likewise must be fitting. The Torah lists “fitting,” or kosher, foods and food preparation rules that enhance our spiritual nature. Kosher rules help us use the physical items in the world to achieve holiness.
Note Many of the halachot listed here differ from the more-stringent approach of the Star-K, even though RMH is the halachic authority for the Star-K. The halachot listed in PRACTICAL HALACHA are the basic halachot and RMH approves of their use for individuals.
What Is Kosher?
What Is Kosher?

By Sara-Malka (Diane) Laderman

Kosher (Hebrew for “fitting” or “suitable”) means foods that comply with certain laws. Kosher rules could be summed up like this:
  • The food must start out kosher
  • The food must stay kosher during processing.

Starting Out Kosher
The Food's Natural State

Rule #1

All Plants, Raw, Are Inherently Kosher

All raw, unprocessed plants are kosher. However, restrictions on produce grown in Eretz Yisrael may apply (teruma, ma'aser, shmita), and orla may apply to produce grown anywhere in the world.
  • For laws about eating perennial fruits, see appropriate listings under Agriculture
  • For laws regarding bugs in plant produce, see below.
Rule #2

All Mammals that Chew Their Cud and
Have Split Hooves Are Inherently Kosher

Kosher mammals are all cud-chewing, split-hooved animals (Leviticus/Vayikra 11:1-8 and Deuteronomy/Devarim 14:3-8). Included are both domestic ("beheimot"--goat, sheep, and cow families ) and wild ("chayot"--deer, giraffe, and wild goat and sheep families) mammals. There are two (sometimes) practical differences between the two groups:
  • You may eat the cheilev (a type of fat) from a wild kosher mammal, and
  • After slaughtering, you must cover the blood from a wild kosher mammal but not a domesticated kosher mammal.
Below is a sampling of kosher mammals:


Q: How can you tell if an animal has split hooves?

1)  Split Hooves Must Be Hooves

Hooves must be made of hoof material--a hard substance similar to your fingernails—not fleshy feet.

2)  Split Hooves Must Be Split

Hooves must be split all the way through from front to back.


Q:  How can you tell if an animal chews its cud?

A:  Watch for the sliding ball.

When a cud-chewing animal starts to eat, you will see it bolting down its food into its first stomach, like a hungry 9th grade boy (much like humans racing to throw groceries into their shopping carts), in case a lion or bear is coming to eat him or her.

Next, it will find a safe place to more leisurely bring up its cud and chew its stash. During cud-chewing time, especially for goats (sheep are usually too woolly to make out shapes), you will distinctly see:

  • Racketball shape popping up the goat's throat, 
  • Goat's cheeks ballooning out and its lower jaw chewing in a horizontal figure-eight pattern, and, a little later,
  • Racketball shape sliding down the throat again.  

You will soon see the shape of a new racketball pop up the throat.

By contrast, a non-kosher animal will chew slowly and well the first time—it will not have another chance to chew its food later, like the kosher animals do.  

Note Kosher animals' four stomachs do a great job of completely digesting whatever they eat. That's why smart gardeners will only fertilize their gardens with dung from cud-chewing animals, because the dung from non-kosher horses and donkeys contain many undestroyed weed seeds that will sprout and take over their gardens.


Animals in the camel family (camel, llama, alpaca, vicunya, etc.) appear to have split hooves when seen from the front.  These are actually just two long toenails in front of a padded, fleshy, incompletely split foot, which you can easily distinguish as a whole foot when looking from the back.

One non-kosher animal has great-looking split hooves but doesn't chew its cud—animals from the pig family.

Insight from Masechet Chullin

All kosher mammals inherently have horns; all non-kosher animals are hornless.  Bottom line:  If you find a horned animal, it's definitely kosher.

But horns are not a halachic requirement from the Torah like split hooves and cud chewing are, which is a good thing, since some breeds of goats, sheep, and cows are naturally “polled” (born hornless) or their horn buds were removed when they were young to prevent damage later.

Note Unlike for birds, we don't need any tradition (masoret) to identify kosher mammals. We rely entirely on the two signs: cud-chewing and split hooves.
Rule #3

All Fowl That Have “Masoret” Are Inherently Kosher

Not everyone's agreed as to what the Torah means by a “netz” or a “yanshuf.”  So when Leviticus/VaYikra 11:13-19 lists the 20 non-kosher flying species—allowing us to eat anything NOT on the list—we ignore the list and just eat what we know our ancestors traditionally ate as kosher.  This tradition is known as masoret.

In the US, we eat all breeds of chickens and--in most circles--turkey, all breeds of goose except those whose beak is black (such as the Canadian goose) or whose beak does not go straight back to its forehead (like the Chinese goose), and Peking duck (we don't eat mallard or Muscovy ducks or their close relatives).

In Israel, additional birds eaten as kosher include mallard and Muscovy ducks, guinea fowl, Couternix quail, pigeons, and turtle doves.

Note Some Jewish families originating in Germany, Iran, and other places maintain their masoret on eating pheasant, and you may be able to receive masoret on various species from researchers such as “The Aris”--Dr. Ari Greenspan and Rabbi Dr. Ari Zivotofsky, both Jewish ritual slaughterers (shochtim) who have spent the last 20 years interviewing and videotaping elderly European and Sefardi immigrants to Israel as to what birds they ate as kosher in their home countries. You can google their work or read some of Dr. Zivotofsky's articles on

Zivchei Cohen, a book written and published by a Jewish ritual slaughterer (shochet) in Italy, shows colored illustrations of 29 species known to be kosher, including peacock, pheasant, Couternix quail, mallard duck, and numerous songbirds.  Maor L'Masechet Chullin U'Vechorot (vol. 2, Feldheim, pp. 29-33) reproduces these colorful illustrations and names each bird in five languages, noting that the 29 were listed to acquaint students of Jewish ritual slaughter (shechita) only with rarer birds' identities and that the well-known kosher species were not included in the 29!

Chazal noted that kosher birds share certain characteristics:

  • They sit on a branch with three toes in front and one in back.  Non-kosher birds usually sit two and two, as they need equal strength on both sides of their feet for killing and carrying off food, except for:
    • Owls, whose feet are flexible and can move their toes to the side, forward, or back, and 
    • Vultures, who need balance walking instead of gripping, since they walk on the ground to eat food that is already dead.
  • They lay eggs that are not entirely round or oval but are, well, egg-shaped, with kad v'chad—a rounded end and a pointed end. Not all egg-shaped eggs are kosher, but all totally round eggs, if from fowl, are not kosher (fish eggs from kosher fish, which are perfectly round, are of course kosher). There are some eggs, including from doves, that seem perfectly oval but are actually kosher.
Rule #4

All Fish That Have Fins and Scales Are Inherently Kosher

This excludes most eels (some conger eels that have kosher scales are kosher!) and all shellfish, catfish, sharks, swordfish, sea urchins, jellyfish, sea slugs, and many other sea creatures.

In addition to commonly eaten kosher fish such as salmon and tuna, some unexpected fish are also kosher, including barracuda, goldfish, and many other pet and tropical fish.

Rule #5


All other creatures, except the four kosher locusts, are not kosher.
NoteThe four kosher locusts are grasshoppers with knees higher than their backs. The four include the chagav, identified by Yemenite Jews by a “chet for chagav” marking on its abdomen.
Rule #6

Kosher from Kosher
Whatever Food Substances Come Out of a Kosher Animal Are Inherently Kosher

except for some fats (cheilev), blood, and the sciatic nerve (gid ha'nashe).

Milk from a cow (a kosher animal) is kosher. Milk from a pig (a non-kosher animal) is not. An egg from a kosher bird is kosher; an egg from a non-kosher bird is not kosher.

Q:  Since bees are not kosher, how can we eat honey? 

A:  Honey is not produced from bee parts, but rather from flower parts.

Rule #7

Animal Blood
May Not Be Eaten in Any Form.

Note Fish blood is not forbidden.

Preparing Kosher
Harvest and Kitchen


What To Check

  • Remove bugs (see Why Bugs May Not Be Eaten)
  • Select fruits and vegetables that have no harvest-related problems such as orla (and in Eretz Yisrael, kilayim, shmita, etc.); separate out teruma and ma'aser from any Israeli-grown produce that requires it (see Teruma/Ma'aser: Ownership: What Is Hefkeir Produce)
  • Make sure that any liquid grape product to be handled by a non-Jew for a Jew has been cooked or pasteurized before being handled.  Cooking turns the wine into an inferior product disqualified for use in idolatrous practices.




Kosher mammals must be slaughtered in the quickest and most humane manner possible, according to halacha.  A highly trained ritual slaughterer (shochet) must perform the slaughtering (“shechita”).  He checks the knife before the slaughtering to ensure there are no burrs to catch on the animal's throat.  He says the blessing “al ha'shchita” and then cuts the windpipe and the esophagus as well as the neck arteries.  After slaughtering, he checks the knife again for burrs (if he finds one, the animal is not kosher) and checks the animal's lungs to make sure the animal wasn't about to die of lung perforation in the near future.  

Certain types of adhesions may be found on the animal's lungs. If they can be removed (by peeling) without perforating the lungs, the meat is kosher. If there are only small and easily removed lesions, the meat is glatt (“smooth”). If there are no lesions at all, the meat is classified as “Beit Yosef.”

Kosher lamb and goat are always glatt/chalak kosher.

NoteThere is no need to eat glatt meat. Meat is kosher if it has been properly slaughtered, de-veined and de-fatted (traibored), and soaked and salted in accordance with Jewish law.

Actually, there are 18 organic or physical defects that may make meat non-kosher but, as a practical matter, we only check for lesions in the lungs and also in the second stomach. 

If the animal proves to have been healthy, it is sometimes hung upside down to allow the arterial blood to drain out. (It is possible to hang the animals before being slaughtered but this is not the usual method). 

Skinning and Traiboring

The animal is skinned.

Next, the animal is traibored. Traiboring removes certain nerves, sinews, blood vessels, and fats that we don't eat, including the sciatic nerve damaged when our forefather Jacob wrestled with the angel at the Jabbok stream.  

In the US, only the forequarters are traibored and eaten, and the hind portion is sold to the non-Jewish consumer. In Israel, the hind portion is traibored too and eaten as kosher.

May you traibor meat once it's cooked?  And if not, how did Jews traibor more than 1 million Passover lamb offerings that had to be slaughtered and prepared between midday and evening (and it takes 2-3 hours to traibor one lamb!). The Jewish commentator The Raavad says the Passover lamb was traibored before roasting; Rambam disagrees, since the lamb had to be roasted whole. Rambam opines that the sinew, unlike fat, does not impart its flavor to the meat and that people would just traibor the Passover offering meat on their plates.

Removing Blood

The next steps involve removing blood (“kashering”) and can be done at the butcher's or at your home.  The meat is cut, rinsed, soaked for at least 30 minutes, put on a slanted board to allow the blood to run off, and covered with kosher (a coarse) salt for one hour.  After being rinsed three more times, the meat is now kashered.

Note Not all blood is not kosher! There is a difference in Jewish law between “moving blood” (which is not kosher) and other types. So, if you see some blood or other red liquid inside meat that has been already made kosher, it is not considered to be blood. For blood that has pooled outside of the meat, see Introduction to Blood in Meat.

Preparing the Liver

The liver is cut halfway through several times and covered with kosher salt top and bottom.  You can oven broil the liver on a rack reserved for that purpose. The blood must be able to drain away from the liver 

You can instead broil the liver over a fire outdoors.  Grilling outside will give the liver a delicious smoky flavor that even children like--but do NOT allow the neighborhood cats to steal your livers off the grill!  


Covering Blood

Kosher fowl is slaughtered and, when it stops flapping, is usually hung upside down to allow the arterial blood to run out and onto the earth. Cover all the blood with dirt (a mitzva from the Torah--mitzva d'oraita) and say the blessing “al kisuy dam b'afar.”


Rinse with water and remove the feathers. Defeathering can take a while for chickens and up to two hours for one small duck, especially if you are saving the down!  

NoteAlthough the non-kosher world will dip the bird in hot water to open the pores and make the feathers easier to pull out, we cannot yet heat (this is like cooking) the bird because it is not yet kashered.

Removing Internal Organs

Rinse the bird. Usually, a circle of flesh surrounding the anus is cut out.  Start pulling out the digestive system.  Recognizable items such as the liver, heart, and giblets will come out and eventually you will be able to stick in your hand and pull out the lungs.  This is not as cold and unpleasant as it sounds because the bird will be warm for quite a while.


Once the bird is defeathered and the internal organs have been removed, rinse and salt with kosher salt inside and out and put it on a slanting board for an hour. Rinse three more times and cook!

Preparing the Giblets

Cut off the hard coating at one end of the giblets and rinse out the fine sand within. Remove the yellow internal lining.  Salt and kasher with the rest of the bird.

Preparing the Liver

To kasher the liver, see Preparing the Liver, above, for meat liver.

NoteCurrently, all kosher poultry in the USA is mehadrin (enhanced level of kosher), but not all kosher poultry slaughtered in Israel is mehadrin (due to organic defects).


Buying Fish

Kosher fish bought from a store in which non-kosher fish are also sold should have any cut surfaces scraped and should be rinsed before using. Ideally, the knife that cuts the fish should be washed with soap and water beforehand. 


Chagav Grasshoppers

Not much preparation needed here. Many Yemenites just twist off their heads and eat. B'tei'avon!

Substances from Animals


Dairy must be kept separate from meat, with a separate set of pots, pans, servers, scrubbers, and dishpans each for dairy and meat. See Kashrut: Dairy/Meat Combinations.


Eggs must be checked for blood spots.  Throw out a fertilized egg with a blood spot. You may remove the blood in the white of the egg and eat the rest of an unfertilized egg, but the custom is to not eat the egg at all.

Unwanted Additives

Manufacturing Aids

In the US, food manufacturers are allowed to add “manufacturing aids”--even more than 1/60th of the volume of the other ingredients--without listing them. Some foods therefore need special supervision to ensure non-kosher substances have not been added.


  • Kosher oils may be deodorized by heating them in vats that previously contained non-kosher oil, which renders the formerly kosher oil non-kosher. Or they may be put into tankers previously used for non-kosher liquids.
  • Food colorings may come from the cochineal insect, which is non-kosher, and flavorings may be derived from the musk of non-kosher animals.
  • Cheeses may have non-kosher rennet or pig milk added. Also, the rabbis of thousands of years ago made an injunction that even where the ingredients are kosher, cheese still requires kosher supervision.
  • Maple syrup in the vat may be stirred with bacon (which is non-kosher) to reduce the froth produced by boiling.  
  • Candy may include non-kosher oil that is put into the molds so the candy does not stick.
  • Kosher meat might not be kosher for Passover.

Transference of Taste (Ta'am)

Sometimes dairy will spatter onto a meat utensil, or someone will set a hot pot of kosher food into a non-kosher sink.  Or someone will cut a lemon or onion with a dairy knife and then put the lemon into a pot used for meat.  What happens next depends on whether the offending substance was:

  1. Charif (spicy/sour/strong) enough to transfer the taste to the new item.
  2. Hotter than yad soledet bo (too hot to hold your hand in it for a few seconds—about 120° F, or 49° C).
  3. More than 1/60th of the total volume.
See following halachot for what to do next.

Kitchen Set Up

A hungry Martian landing in a modern kosher kitchen must assume earthlings eat in binary: Ideally, two sinks. Two dish towels.  Two sponges.  Two dishpans. Two cutting boards.  Even, if the owner is fortunate, two dishwashers.

And what about those strange markings on the pots, pans, and servers?  Perhaps he'll find a bright splotch of red paint or an “F” (for fleishig--Yiddish for “meat”) lettered in nail polish on utensils in the left cabinets.  Blue paint or nail polish, or an “M” (for milchig--Yiddish for milk) on utensils in the right cabinets. The plates, bowls, and silverware in left cabinets do not in any way match those in the right cabinets. Somewhere in a central cabinet, pots, pans, and servers are painted with a white dot, marked with a “P” for pareve, or left unmarked.

Opening the pantry, little symbols jump out from canned and packaged goods.  Star-K, O-U, O-K, KOF K…..  Only the dried beans and grains seem symbol-less.  And the freezer?  Well stocked but no frozen bacon, pepperoni pizza, and shellfish TV dinners.…

How do these people eat?

The Great Divide

Separating Dairy and Meat

Welcome to the world of dairy and meat. Most kashrut problems in the kitchen involve the transfer of milk or meat flavor to the other gender by means of heat or, less commonly, by hot/spiciness.

It's easy to be jealous of vegetarians, or people who only eat plants and dairy products or who only eat plants and meat products!  They never confuse their pots and serving utensils or deal with spatters of hot dairy foods onto meat utensils or vice versa.  Large institutions and kosher cafeterias, similarly, may not have these mix-ups, since they can usually devote a whole room to a dairy or a meat kitchen.

Here's how the rest of us live:


If you can, designate some countertops for dairy and some for meat.  This will help you stay organized spatially.  If you have only one sink, you may need to use the counter to the left for one dishrack (dairy or meat) and the counter to the right for your other dishrack. 

Some countertop materials, such as granite, can be kashered by pouring boiling water over them.  This will make the counters kosher and pareve (neutral--not dairy or meat).  Once you have kashered your counter(s), you will be able to set down hot utensils, pots, and pans directly onto the counter (dairy utensils on your designated dairy counter; meat utensils on your designated meat counter). 

If your countertop is not kosher or kasherable, you will need to cover the countertop before setting down hot (above 120° F) utensils, pots, and pans. Trivets work fine but so does a simple piece of corrugated cardboard in a pinch.  

Dishes and Flatware

If feasible, select different patterns of dishes and flatware for dairy and meat so you can tell them apart.  It is helpful to store the dairy and meat dishes in separate locations, preferably close to the counter of its gender. Porous dishes (stoneware, china, ...) cannot be kashered once used for hot non-kosher food and cannot be changed from one gender to the other. Metal dishes generally can be kashered. Glass only assumes a gender if it is placed directly on a fire or other heat source (to at least boiling temperature) or into a hot oven, so even if you pour boiling water or hot food into a glass bowl, such as hot pasta, and add cheese or other dairy food, the bowl remains pareve (or whichever gender it was previously).

Sinks and Dishracks

If you don't have two sinks--one for dairy and one for meat--and must use the same sink for both, try to choose different colors for your dairy, meat, and pareve dishpans, dishracks, and sponges/scrubbers (or sponge holders). If not, distinguish your dairy dishpans, dishracks, and sponges/scrubbers (or sponge holders) from your meat ones by placing them on opposite sides of the sink. Neutral, or pareve, dishes/cookware require a third sponge and dishpan. In a pinch, you can wash dishes, pots, and utensils by holding them in the air or placing them on a counter (whether either kashered or not) next to the sink as long as the dishware, pots, etc., do not reach 120° F.  


You can designate one drawer for dairy flatware and a second drawer for meat (and a third drawer for pareve). Color-coding or purchasing “dairy” and “meat” stickers to place on the outsides of cabinets and drawers can be especially helpful if anyone else will be cooking/washing dishes in your house and doesn't know your kitchen well.  

Cooking Utensils/Food Processors

Distinguish your cooking utensils (your choice of colors) for dairy, meat, or pareve by using paint or nail polish, using different patterns, or even different shapes (one person uses round baking dishes for dairy and rectangular ones for meat!). If you lack drawer space, hang utensils from the wall or overhead rack or put them on your counter in jars color-coded for dairy, meat, or pareve. In a pinch, colored electrical tape can be used temporarily to mark dairy or meat servers or serving pieces (until it falls off during washing or turns black in the oven…).

You will only need one blender, blending stick, bread machine, mixer, food processor, etc., if you always keep them pareve.  Otherwise, you may need duplicates of these items. Color-code them as well.

Stove Burners

To kasher a non-kosher stove burner, clean off any hard deposits on the grate, cover the burner with a sheet of metal (to hold the heat on the grate), and heat it full-blast for 45 minutes. (See halachot below for kashering burners by putting them in the oven.) 

NoteYou do not need to kasher a burner between uses for dairy or meat because the burner's heat keeps it kashered.


A stainless steel stovetop can be kashered, but a ceramic one (due to porousness) might not be kasherable-consult a rabbi.  When cooking, place an appropriate spoon rest or bowl nearby (for dairy or meat, depending on what you are cooking) to hold your hot stirring spoon or spatula. This way, you won't need to set down your hot stirring utensil onto a non-kosher countertop or stovetop, or place a hot dairy stirrer where you previously set down a hot meat spatula.  


You can kasher a non-kosher oven by cleaning off any accumulation of old food (whether burned on or not, it must be removed) and turning up the oven full blast for 40 minutes.  You may use the same oven for dairy and meat foods if you always keep either the dairy or meat covered. Consider the oven to be one gender and always cover liquid foods of the opposite gender (dry foods do not require a cover).

Cutting Board

If you only have one cutting board for fruits and vegetables and one knife, you may want to keep them pareve. The main kosher problems with knives and cutting boards happen when cutting a fruit or vegetable with a strong-spicy taste that can transfer the milk or meat status of one utensil or food to another.  Such items are garlic, lemon, onion, and sour apples, and sour grapefruits.


  • Garlic was chopped with meat knife on a dairy cutting board (rendering the garlic, the knife, and cutting board non-kosher), or
  • Onions cut with a dairy knife were tossed into a boiling meat pot (rendering the pot and contents non-kosher unless the onions were less than 1/60th the volume of the pot's food). 


Glasses, washed, can be used for a dairy or meat meal. You can use the same salt and pepper shakers and clean glasses for dairy and meat; however, it is recommended to use separate salt and pepper shakers since you might have food of one gender on your hands when you use the shakers of the opposite gender. If you typically use a table for serving either dairy or meat, and want to serve the opposite without switching tablecloths, lift the tablecloth and use the original table surface or cover the tablecloth with placemats. If one person wants to eat dairy and another wants to eat meat at the same time on the same table, place a reminder to remind them not to mix the foods (different placemats or tablecloths, physical barrier between the people's dishes, etc.).


Let's say you don't keep kosher and want to have your kosher-observant friend over. What to serve?

As long as your utensils are clean, you chose kosher foods (see Going Shopping, below) or fresh fruits and vegetables, nothing gets 120° F or above, there is no involvement of anything spicy (charif), and you don't mix dairy and meat (don't offer a kosher bologna sandwich with kosher Swiss cheese!), everything should be OK. Some people will prefer if you serve them using disposable plates, bowls, flatware, and cups; if you are Jewish, you should only serve on disposables. Some will prefer to be in the kitchen during food preparation. Don't be offended; it's hard to keep track of everything to remember even in a kitchen set up for being kosher!

You might want to keep the wrappers or containers from any processed food so that the kosher guest can see what you actually are serving and check for the ingredients or for a kosher supervision symbol.


Major towns usually have at least one kosher supermarket, but you can find plenty of kosher food in regular supermarkets too. (Even in Salt Lake City, home of the Mormons, a major supermarket chain sells Empire Kosher Chickens!) Here are some tips:

  • You may consider all fresh and uncut fruits and vegetables to be kosher. Sharp-flavored fruits and vegetables such as garlic, when cut, must be cut with a kosher utensil.
  • Look for a kosher symbol (“hechsher”) on prepared foods (except those foods that do not need a hechsher—see When Hechsher Needed  and When Hechsher NOT Needed).

For more information on kosher symbols and on what goes into certifying a prepared food as kosher, see this link:


The basic reason that Jews only eat kosher food is because God commanded us to do so. There are many explanations of how eating kosher benefits us. One approach is that kosher food enhances the spiritual well being of the Jewish people. That holiness is blocked when we eat non-kosher.

While kosher food raises us up spiritually, we raise it up too. When we say the correct blessing before or after we eat, we acknowledge that God is the food's true source. When we use food's resulting health and strength to perform God's commandments, we reunite our food and ourselves with our higher purposes, “rectifying the world.” That brings spiritual and physical blessing down to us and to the world.

You don't want a rapacious spirit?  Don't eat predators. You don't want to think like a bottom-feeder? Don't eat scavengers—whether catfish or vultures or pigs—or reptiles, amphibians, or bugs (except kosher grasshoppers!). You don't want to be callous? Don't eat the life-blood of a bird or mammal—or even the bloodspot of an egg. You don't want to be cruel? Make sure the animals you eat were slaughtered quickly and humanely. Don't want to separate yourself from worshipping the Only One? Don't drink wine or grape juice that could have been used for idol worship.

And non-Jews? Shouldn't they keep kosher too?

Non-Jews must keep only one kosher law--aver min ha'chai. This means non-Jews, like Jews, may not cut off and eat the limb of a live animal.

We can come up with numerous explanations for why keeping kosher is healthier, more pleasant, more logical, or more spiritual than eating non-kosher. But the bottom line is, we do it because God says to, we are here to serve Him, and we trust that God wants what is best for us!

Kashrut: Concepts
Kashrut: Terms
Kosher means fitting (food that is fitting to eat).
Nifsal MeiAchilat Kelev
Nifsal mei'achilat kelev means not fit for a dog to eat. Since dogs will eat many things that are disgusting, food is considered edible by whether you would serve it to a dog. Toothpaste and lipstick (all year round, not just on Passover) are examples of nifsal.
Trafe and Neveila
"Trafe" is generically used to mean any food that is not kosher, but it actually means an animal that was “torn” (for instance, by a predator).
Neveila is an animal that was not slaughtered in accordance with Jewish law.
Kashrut: Supervision/Hechsher
Kashrut: Food Served by Shomer Shabbat Jew
Kashrut: Food Served by Shomer Shabbat Jew
You may trust that the food a shomer Shabbat Jew serves is kosher without your needing to check it out.
However, if a shomer Shabbat host serves non-kosher food or food without reliable supervision on foods that need supervision, you may not eat it.
Note If the host will listen to you if you tell the host that the item is not kosher, you should tell him/her. If the host will not listen, you should not tell him/her.
Kashrut: Food Sold by Stores or Caterers
Kashrut: Supervision Mark
Supervision is needed during the manufacturing of certain foods to certify they are kosher. These products are usually marked with a supervision mark (“hechsher”) of the certifying body.
Kashrut: Reliability of Supervision
Ask a reliable source when you need to determine whether a particular kosher-supervision body is reliable. You do not need to do any further research.
When Hechsher NOT Needed
Processed Food without Hechsher: Is It Kosher?
If a processed food does not have supervision/hashgacha, here are some issues to consider:
  • Ingredients;
  • Utensils/processing equipment;
  • Bishul akum/“prestigious” foods that require Jewish involvement in the cooking;
  • Heating system (recirculated steam?);
  • Heter for milk without being supervised - which conditions and countries can be relied on;
  • Non-food ingredients (lubricants, preservatives, emulsifiers...);
  • Reliability of the producer;
  • Is the non-kosher ingredient batel/nullified?
    • ownership (Is the food's producer or owner Jewish?)
    • intended consumer (Is the food being produced specifically for Jews, or is it for the public and Jews are some of the customers)?
    • Was the non-kosher substance added intentionally?
    • Does the non-kosher substance have flavor?
    • Was the non-kosher substance added for flavor?
A hechsher/kosher supervision is not needed on:
  • Beer made in the US (and sometimes in other countries).
  • Nuts (dry roasted) without additives.
  • Olives--assumed to be kosher unless mixed with ingredients that may be non-kosher, such as:
    • Vinegar (sometimes made from grapes).
    • Non-kosher chemical preservatives (in commercially sold olives).
    Note In open markets in which olives are sold in bulk, you may eat olives after checking the ingredients.
  • Olive oil (extra virgin).
  • Pure fruit juice NOT made from concentrate (such as orange or pineapple juice) does not normally require a hechsher (except for grape juice, which always requires a hechsher!).
    Note Juices from concentrate might have kashrut problems due to the vats in which they are cooked or pasteurized. If you can verify how the juice was processed and that there are no kashrut problems, you may use the juice without a hechsher. There may also be problems with juice made from fruit or vegetables which were grown in Eretz Yisrael, due to orla, shmitta, teruma and maaser.
  • Scotch whiskey--even where it might have been aged in sherry casks.
    Reason Any sherry would be nullified as less than 1/6th. 
    Note Other types of whiskey may not be kosher because:
    • Glycerine may have been added;
    • The whiskey may have been owned by a Jew during Passover in a previous year; or
    • Milk, or alcohol derived from milk, might have been added.
  • Sugar (confectioner's) needs kosher supervision only for Passover. Regular sugar never needs kosher supervision (currently).
  • Unprocessed foods such as
    • Raw fruits and vegetables (but might need to be checked for insects), and
    • Water, but some unfiltered tap water might have tiny creatures in it which make the water non-kosher.
Note Several websites list additional foods that do not need supervision to be trusted as kosher.
When Hechsher Needed
A hechsher/kosher supervision is needed on:
  • Seltzer with natural flavor.
  • Grape seed extract and grape seed oil.
Kashrut: Taste (Ta'am) Transfer
Introduction to Taste (Ta'am) Transfer
Introduction to Taste (Ta'am) Transfer
Gender/Kashrut Status Transfer
Foods and kitchenware (pots, pans, dishes, utensils, and containers) can absorb taste from each other and so adopt a new gender or kosher status. They can change from:
  • Kosher to non-kosher,
  • Kosher pareve (neutral) to kosher dairy or kosher meat, or
  • Kosher Passover to kosher (or non-kosher) non-Passover.
Note You can sometimes change a utensil/container to kosher-pareve (see Kashering, below), but you cannot change a
  • Gendered food to neutral-pareve, or
  • Non-kosher food to kosher.
Taste Absorption
Taste gets absorbed in three ways: Heat, pressure, and soaking. 
To absorb taste, and therefore gender or kashrut status, through heat, a food or utensil must be heated to 120° F or more while:
  • Steamed with a halachically “liquid” foodor
  • In wet physical contact with the food or utensil.
  • Two hot pans, which are clean on their outsides, only transfer taste from one to the other if they are wet on the outside and are touching each other.
  • A hot utensil placed onto a counter only transfers gender to the countertop if there is liquid or food at the point of contact.
Note  All liquids plays a major role in facilitating taste transfer.
NOTE Taste, gender, or non-kosher status do not travel upstream into the utensil that food is being poured from. Even if you pour hot liquid (pareve or of one gender) from a pot onto a non-kosher or opposite gender food, the genders are not transferred back through the stream of liquid to the pot, even if any or all of the elements are more than 120 degrees.
Situation You pour hot liquid from some pareve vegetables into a non-kosher sink that had hot in it within 24 hours. There are dishes or utensils in the sink.
Status The dishes do not change gender unless the hot liquid fills up from the sink onto them. If so, the dishes or utensils become non-kosher. But no gender change occurs through the stream of liquid back to the pot of vegetables.
Note If the non-kosher sink had not had anything hot (120 degrees or above) in it for at least 24 hours, no change of gender or kosher status happens at all.
Note On Passover, gender and chametz status DO get transferred through a stream of hot liquid.
To absorb taste, and therefore gender or kashrut status, through pressure or short-term soaking, one of the items must be spicy/charif.
To absorb taste, and therefore gender or kashrut status, through long-term soaking, the food must soak for specific amounts of time.
Note If the food or utensil is not hot (120° F or more), is not spicy/charif, and is not soaking for a long time, there is no gender or kashrut-status transfer.
You may use a non-kosher utensil for any cold food of the opposite gender, so you may:
  • Eat cold (kosher) cereal out of a meat or non-kosher bowl, or
  • Use a meat or non-kosher spoon to eat kosher ice cream.
Note Even though these are permissible, they may not be done regularly but only on an ad hoc basis.
Food and Kitchenware: Which Influences What
Hot or Spicy/Charif Foods
With hot (more than 120° F) or spicy/charif foods:
Foods and utensils/containers transfer taste to each other.
Cold or Non-Spicy Foods that Soak
With cold (less than 120° F) or non-spicy/charif foods that soak:
  • Foods do not transfer taste to utensils/containers;
  • Utensils/containers do NOT transfer taste to foods.

NOTE No substances (not salt, or any food...) absorb gender from the open air.
The 24-Hour Rule: Eino ben Yomo
Torah Law: Reverts to Kosher-Pareve
By Torah law, a utensil/container always reverts to kosher-pareve after 24 hours (since the taste of any absorbed food becomes ruined with time). 
Rabbinic Law: Must Be Kashered
However, by rabbinic law, the utensil/container must be kashered before using.
NOTE Even by Torah law, a hot or spicy/charif food can revive the milk-meat or non-kosher status of another utensil/container (see below) even after 24 hours.
Accidentally or Intentionally
Food Hot and Accidentally Placed; Utensil Not Hot for 24 Hours
Kosher food hotter than 120° F (49° C) remains kosher if accidentally placed into a non-kosher, clean utensil that has not been heated to 120° F or more for at least 24 hours.
REASON After 24 hours, b'di'avad, the utensil has reverted to being kosher-pareve.
NOTE If the utensil had been “used” (heated to 120° F or more) within the preceding 24 hours, the hot food that accidentally entered the utensil would be non-kosher. Ask a rabbi for possible exceptions.
Food Hot and Intentionally Placed
If the hot food had been put into the utensil intentionally, the food would not be kosher.
REASON Chazal made a rule (takana) that if you intentionally place food of one gender into a utensil of the opposite gender and heat it to 120° F or more, the food is not kosher.
Taste (Ta'am) Transfer: Heat
Taste (Ta'am) Transfer: Heat: What Is Hot (Yad Soledet Bo)
Taste (Ta'am) Transfer: Heat: What Is Hot (Yad Soledet Bo)
 “Hot” is 120° F (49° C).  This is the temperature at which an average person cannot hold his/her hand in a food for more than a few seconds (yad soledet bo).
Taste (Ta'am) Transfer: Spicy/Charif
Taste (Ta'am) Transfer: Spicy/Charif: What Is Spicy/Charif
Which Produce Is Spicy/Charif
Spicy/charif fruits and vegetables include:
  • (Sour) Apples
  • Chives
  • Garlic
  • (Tart) Grapefruits
  • Horseradish
  • Lemons
  • Limes
  • Mustard (fresh or prepared)
  • Onions
  • (Sour) Pineapples
  • Radishes
  • Scallions.
Judge the tartness of food by a sour apple: if the food you are judging is less tart, it is not spicy/charif.
Note Dried chives, onions, and garlic might be spicy/charif, depending on the individual product.
Taste (Ta'am) Transfer: Spicy/Charif: Factors that Affect Spicy/Charif
Taste (Ta'am) Transfer: Spicy/Charif: Mixtures
Taste (Ta'am) Transfer: Spicy/Charif: Mixtures: Diluted with Oil
Spicy/charif will not pick up gender if the spicy/charif taste is diluted by oil and it no longer tastes spicy/charif. Mixtures with a strong taste, containing pepper, lemon juice, garlic, etc., will pick up the gender of their container if in the container long enough to become cooked.
Example Garlic oil will pick up gender of its container if in the container long enough to become cooked.
Taste (Ta'am) Transfer: Spicy/Charif: Mixtures: Batel BaShishim
Spicy/charif food may become nullfiable (batel ba'shishim), but consult a rabbi about the exceptions and details.
Taste (Ta'am) Transfer: Spicy/Charif: Heat
Taste (Ta'am) Transfer: Spicy/Charif: When Cooked
Some spicy/charif foods, such as onions, lose their spicy/charif nature when cooked.
Taste (Ta'am) Transfer: Spicy/Charif: Pressure
Taste (Ta'am) Transfer: Spicy/Charif: Pressure: What Acquires Taste
Pressure can transfer taste from spicy/charif food to utensil/container or vice versa.
Taste (Ta'am) Transfer: Spicy/Charif: Pressure: Types of Pressure
Here are some types of pressure that transfer taste from spicy/charif food to utensil/container or vice versa.
When a spicy/charif food is:
  • Cut with a knife,
  • Crushed,
  • Squashed by a spoon or fork,
  • Squeezed in a garlic press, or
  • Juiced in a juicer (including in a plastic orange juicer with plastic done that fits under the half-orange and spins slowly back and forth electrically).
Taste (Ta'am) Transfer: Spicy/Charif: Pressure: Food Absorbing Taste of Utensils
When a spicy/charif food takes on the gender of the cutting/squeezing utensil:
  • You may not cook or eat that food with food of the opposite gender.
  • However, you MAY eat the opposite-gender food immediately after eating the gendered spicy food without waiting.
Situation An onion is cut with a meat knife, on a meat cutting board:
  • The onion acquires meat status.
  • You MAY NOT later cut this onion with a dairy knife or on a dairy cutting board. (If you do, the onion, the dairy knife, and the dairy cutting board will all become non-kosher.) 
Exception If the knife and cutting board had not been used (even for cold items) for at least 24 hours, consult a rabbi.
Exception If you can sand off the surface to below the level of any knife cuts, the board might be kosher. Consult a rabbi
  • You MAY NOT cook this onion in a dairy utensil.
  • You MAY NOT eat this onion with dairy food.
  • You MAY eat dairy immediately after eating this onion (as long as there is no actual meat mixed into the onion).
  • You MAY cook this onion with fish (even though you may not cook meat and fish together) but the fish may not be eaten with dairy food.
Situation You cut an onion with a meat knife and fry it in a neutral/pareve pan.
StatusThe pan becomes meat, but consult a rabbi for possible leniencies.

Situation You cut an onion with a meat knife and fry it in a dairy pan.
StatusThe pan becomes non-kosher.  If you cook a neutral/pareve food in that pan after 24 hours have passed since the onion was cooked in it, and you ate the pareve food with milk, it is OK b'di'avad but you may not do that l'chatchila.
Taste (Ta'am) Transfer: Spicy/Charif: Non-Kosher Utensils
A non-kosher fork, knife, or spoon may not be used to eat or cut spicy/charif food, such as tart pineapple. (If the food is not spicy or hot, you may use a clean, non-kosher utensil on an ad hoc basis.)
Example A non-kosher implement (fork, knife) that is stuck into a spicy/charif or salty food, such as a spicy pickle, will make that pickle non-kosher immediately.
Suggestion Cut onion, garlic, and other spicy/charif foods on a pareve board and with a pareve knife.
Taste (Ta'am) Transfer: Spicy/Charif: Pressure: Utensils Absorbing Taste of Food
If you use a neutral/pareve utensil with pressure on a gendered spicy/charif food, you may not use this utensil with food of the opposite gender unless they are all clean and less than 120° F (49° C) and even then, only on an ad hoc basis, not as a regular practice.
Taste (Ta'am) Transfer: Spicy/Charif: Pressure: Blade Sharpness
When cutting a spicy/charif food, pressure (not the physical sharpness of the knife's edge) transfers taste.
Note There is more likely to be higher pressure when cutting with a dull knife rather than with a sharp one!
Taste (Ta'am) Transfer: Spicy/Charif: Pressure: Forgotten Gender
Situation You forgot the gender of a cut onion in the refrigerator.
What To Do
  • You may eat the onion with pareve food.
  • You may NOT use the onion with dairy or with meat. 

Taste (Ta'am) Transfer: Spicy/Charif: Sitting in Container
Cold, spicy/charif, solid food (with no liquid) does not transfer gender UNLESS it was under pressure, so simply sitting in an opposite-gender or non-kosher container does not have any effect.
Note Cold, spicy/charif, liquid food sitting in an opposite-gender or non-kosher container is kosher only if it sat less time than needed to become cooked.
ExampleYou ate cold (less than 120° F, or 49° C) spicy/charif food of one gender on a cold plate of the opposite gender:
Liquid Food
If the cold spicy/charif food is liquid but it is in contact with a utensil of the opposite gender for less time than it takes to boil, it would be kosher but, again, you should only do this ad hoc.

Also see Spicy/Charif Soaking: Long Enough To Be Cooked: Food and Utensil.

Taste Transfer: Soaking
Non-Spicy/Non-Charif Soaking: 24 Hours or More
Non-Spicy/Non-Charif Soaking: Transfers Taste to Utensil/Container
A non-spicy/non-charif liquid or food with any liquid (enough to pour, but that may be even one drop) that sits for 24 hours or more will transfer gender or non-kosher status to its container.
Situation Dairy or meat liquid-containing food is in pareve container.
StatusContainer will become dairy or meat (regardless of intention). 
  • Milk sitting in a pareve mug for 24 hours or more would make the pareve mug dairy.
  • Chicken soup sitting in a pareve stoneware bowl for 24 hours or more would make the bowl meat.
Note This does not apply to any type of cold glass container and the food and the container remain kosher

Non-Spicy/Non-Charif Non-Kosher Soaking: Makes Kosher Food Non-Kosher
Any non-spicy/non-charif, non-kosher food that soaks (in water or any other liquid) with kosher food for 24 hours or more will render the kosher food non-kosher. 
Spicy/Charif Soaking: Long Enough To Be Cooked
Spicy/Charif Soaking: Long Enough To Be Cooked: Food and Utensil
Food soaked in brine, vinegar, or any spicy liquid for long enough to be cooked if heated on a burner or in an oven will absorb or transfer gender or non-kosher status from/to any utensil used with it.
Situation Neutral/pareve food in brine, such as spicy pickles or spicy olives, sits in a container for long enough to become cooked.
  • If the container is dairy, the food will become dairy.
  • If the container is meat, the food will become meat.
Note You may not eat this formerly pareve food with food of the opposite gender.

Situation A pickle with spicy/charif pickle juice is placed into a dairy utensil/container (even if unused) for long enough to become cooked.
Status The pickle will become dairy and may not be eaten with meat.
Note This example does not apply to any type of glass container.
Note Food soaked in brine by a non-Jew does not become subject to bishul akum.
NoteEven if the utensil had not been used for more than 24 hours, a spicy/charif food will “revive” the gendered or non-kosher taste in the utensil. The utensil will then make the food gendered or non-kosher. Consult a rabbi for possible exceptions.

Food Nullification
Food Nullification: Foods
Introduction to Food Nullification: Foods
Introduction to Food Nullification: Foods
Categories of Batel/Nullification
Categories of nullification of non-kosher ingredients:
  • Never batel.
  • Batel b'shishim when the non-kosher substance is less than 1/60th of the total volume of the food.
  • Batel barov when the non-kosher substance is less than 1/2 of the total volume of the food.
When Can a Non-Kosher Substance Be Nullified in a Mixture?
Whether a non-kosher substance can be nullified in a mixture depends on 3 factors:
  • Whether the owner is Jewish;
  • Whether the intended eaters are Jewish; and
  • Whether the non-kosher substance was added intentionally as non-kosher.
If the answers to all three cases is yes, the food is never batel.

Food “Nullified in 60 Parts”:
Accidentally Adding Non-Kosher to Kosher Food 
Batel ba'shishim, or “nullified in 60 (parts)” is food that remains kosher despite the accidental addition of 1/60th or less in volume of non-kosher or restricted food, since at this proportion the non-kosher food's taste becomes negligible.
Taste: If the non-kosher substance: 
  • Has no taste, it is batel barov.
  • Has a taste but the eater cannot taste it, it is batel b'shishim (1/60th).
In all cases, if a substance is added for flavor and can be tasted in the final food, it will never be batel, regardless of whether it was added intentionally (since you can taste it, by definition it was not nullified) and regardless of whether the food was owned by a Jew or not. There are some exceptions. Consult a knowledgeable rabbi.
Some foods do impart their flavor even if less than 1/60th of the total volume of the food and these do not ever become nullified based on the 1/60th rule. Otherwise,  the non-kosher food must be:
  • Less than 1/60 of the volume of the whole.
  • Mixed in and not lying on the surface.
  • Not intentionally added by a Jew.
  • Not listed in “Foods that Never Become Nullified” (below).
Min b'Mino
Substances are only batel when they are similar (“min b'mino”). The substances must be the same type, have the same taste, and have the same appearance (the eater cannot identify them as being different).
Note In such situations, it would be batel barov from Torah (d'oraita) but batel b'shishim (1/60th) by rabbinical order (d'rabanan).
Example A piece of non-kosher meat is mixed in with kosher meat of more than 60 times the volume of the non-kosher piece. The non-kosher meat is batel b'shishim.
Note As a practical matter, this can only apply to ground meat.
Counter Example Non-kosher chocolate syrup or a non-kosher flavored extract mixed into milk or other liquid or onto a solid would NOT be min b'mino even though both are liquids, since their appearances, flavors, and substance are different.

Too Thin To Make Non-Kosher
The thinnest layer of non-kosher fish oil, vegetable oil, soap, or any other very thin substance on food that does not make the food non-kosher is whatever amount cannot be detected by the five human senses.
Foods that Never Become Nullified 
Here are some foods that NEVER become nullified by being less than 1/60th of the main food:
  • Yayin Nesech
    Wine that has been offered to a pagan god or used for idolatrous purposes (yayin nesech) is forbidden in any amount!
  • Mixtures of Milk and Meat
    Mixtures of milk and meat are not ever batel if they were cooked together.
    ExceptionBatel in 1/60th if:
    • You cannot identify either substance AND
    • The mixture is liquid in liquid or solid mixed with solid.
Examples: Milk from a pig mixed with milk from a cow; ground kosher meat mixed in with ground non-kosher meat.
  • Chametz
Any chametz in any amount that became mixed with kosher-for-Passover food DURING Passover is not nullified in 60 parts (batel ba'shishim). 
Note Chametz may be nullified if:
  • Less than 1/60th of the volume of kosher-for-Passover food, AND
  • Mixed with the kosher-for-Passover food BEFORE the holiday began, AND
  • Liquid (solid chametz that got mixed up with kosher-for-Passover food is never nullified).
  • Jew Intentionally Adding Non-Kosher Item
If the non-kosher substance was added by anyone (Jew or non-Jew) unintentionally (he did not realize it was not kosher), the food is kosher/batel b'shishim (1/60th).
If a Jew intentionally adds a non-kosher ingredient to a food, that ingredient never becomes nullified, even if the ingredient is less than 1/60th of the total volume of food and even if the ingredient has no flavor. Note that there are exceptions when non-Jews do the action, especially when a non-Jew adds a non-kosher ingredient or adds stam yainam wine to other liquids.
  • Unflavored or Flavored Non-Kosher Ingredient
    Non-Jew Adds Unflavored Non-Kosher Ingredient
    Situation A non-Jew adds a non-kosher ingredient that has no flavor. 
    Status The non-kosher ingredient is nullified if less than 1/2 of the total (it does not need to be less than 1/60th--batel ba'shishim).

    Non-Jew Adds Flavored Non-Kosher Ingredient
    Situation A non-Jew adds a flavored non-kosher ingredient even if to impart flavor.
    Status The non-kosher ingredient is nullified in 60 parts (batel ba'shishim).
    Note If a Jew had told the non-Jew to add the ingredient, the mixture is non-kosher, just as if a Jew had added it. 
  • Stam Yeinam Added to Water
    Situation A non-Jew adds—to water--stam yeinam (uncooked/non-mevushal) wine that has been handled while open by anyone other than a shomer-Shabbat Jew.  
    Status As long as the wine is less than 1/7th of the final volume, the mixture is kosher
    Note For mixtures with liquids other than water, consult a rabbi
  • Essential Additives
Any additive that is essential to making a food (such as rennet for making cheese, or yeast for baking bread) is NEVER nullifiable.  
  • Food Bought by the Piece
An item that is always bought by the piece (davar she'beminyan) such that even one piece has importance—such as a mango—is never nullifiable.
Situation One mango grown in Eretz Yisrael during a shmita year got mixed in with many mangoes that were grown outside of Eretz Yisrael.
Status Batel ba'shishim does not apply and you must apply the laws of shmita to all of them. 
Note If kosher and non-kosher food items have become mixed up, it is sometimes permissible to eat from the batch of food if most of the items are kosher (batel ba'rov), but a rabbi must be consulted.
  • Important Food
Situation A food with which you could honor a guest (chaticha ha'reuya l'hitchabed), such as 1/4 of a non-kosher chicken or a serving of non-kosher chopped liver, was mixed up with kosher servings—even if more than 60 kosher servings.
Status None may be eaten.
  • Permissible in Future (Davar SheYesh Lo Matirin)
An item that would become permissible in the future (davar she'yesh lo matirin) cannot become nullified by being mixed in with currently permissible foods. 
  • An egg laid on Shabbat will not be nullified by being mixed with eggs laid before Shabbat.
  • Matza made of chadash flour will not be nullified by being mixed with matza made from yashan flour.
  • Whole Insects
An entire insect (briya--whole creature) never becomes nullified even if mixed with other kosher food. 
Note An insect that is not whole MAY be nullified. 
  • Frozen or raw chopped or ground vegetables or spices may be considered kosher even without supervision.
    Reason We assume that any bugs in the food would have gotten partly chopped or disintegrated and therefore nullified.
  • If a recipe calls for chopping or grinding herbs or vegetables, you may do so without first checking them for bugs.
    Note However, if you know there are bugs, you may not chop the food for the purpose of making the bugs nullified:  You must still check for insects before cooking or eating the food and if you see any bugs, you must remove them.
Note You may not eat bugs even if they have been dead for more than 30 days (some people erroneously permit this).
Food Nullification: Utensils (Kashering)
Introduction to Food Nullification: Utensils (Kashering)
Introduction to Food Nullification: Utensils (Kashering)
Food Nullification in Utensils: Torah-Law and Rabbinic Decree
By Torah law (d'oraita), any clean utensil, countertop, etc., automatically reverts to neutral/pareve and kosher after not being heated to more than 120° F (49° C) for 24 hours.
But by rabbinic decree, utensils do not automatically become neutral/pareve even after 24 hours and must be kashered by heat (libun—direct heat; hag'ala—boiling in a pot; or eruy rotchim—pouring boiling water over item) or, if some types of glass, by soaking in water (meluy v'eruy ).
Changing Gender of Utensil
You may kasher a pot or cooking/eating utensil from:
  • Non-kosher to kosher, or
  • Year-round use (chametz) to kosher for Passover.
You may not intentionally kasher a utensil in order to change it from dairy to meat or meat to dairy; you must first kasher it from accidentally (or intentionally) non-kosher to kosher/pareve, or from non-Passover to Passover/pareve. You may then use it for either dairy or meat.

Once you have used it for that gender, the item retains that gender (unless you re-kasher it for Passover or you make it non-kosher first, then kasher it to neutral/pareve).
But if you accidentally heat meat with a dairy utensil or vice versa, you may kasher it back to its original gender by any one of the kashering methods, depending on how it became non-kosher.
Items/Materials that Can Be Kashered
The following materials can be kashered:
  • Glass, including Corelle, if not used directly on the stove or oven. Glass does not change gender or other kosher status unless heated on a flame or in the oven. Unless it is heated in this way, glass does not ever need to be kashered (except for Passover) (see Meluy v'Eruy, below).Glass, including Corelle, if not used directly on the stove or oven. Glass does not change gender or other kosher status unless heated on a flame or in the oven. Unless it is heated in this way, glass does not ever need to be kashered (except for Passover) (see Meluy v'Eruy, below).Glass, including Corelle, if not used directly on the stove or oven. Glass does not change gender or other kosher status unless heated on a flame or in the oven. Unless it is heated in this way, glass does not ever need to be kashered (except for Passover) (see Meluy v'Eruy, below).
   NOTE  Glass used directly on fire or in the oven (kli rishon) cannot
  be kashered except by heating in a kiln.
  • Granite (not granite composite)
  • Marble
  • Wood, if smooth (see notes on Eruy Rotchim, below)
  • Metal, including stainless steel, cast iron, and aluminum.
Note While metal can be kashered if thoroughly cleaned, welded handles and other difficult-to-clean parts may render a metal utensil not kasherable. You might be able to use libun kal on the problematic area and still use hag'ala for the remainder of the utensil.
Items/Materials that Cannot Be Kashered
  • China
  • Corian
  • Corningware
  • Crockpot
  • Formica
  • Glass that has been used directly (kli rishon) on a stove or in an oven; however it can be kashered in a kiln
  • Granite (composite)
  • Knives with Plastic Handles (knives with wooden handles may be kashered if there are no cracks in the wood and if the rivets do not have spaces that catch food and prevent you from cleaning it completely)
  • Mixer-there might be exceptions. Consult a rabbi.
  • Plastic
  • Porcelain (Enamel)
  • Pyrex (if used directly on stove or in oven--kli rishon)
  • Rubber (synthetic)
  • Silestone
  • Silverstone
  • Stoneware
  • Teflon
  • Toaster/Toaster Oven
  • Waffle Iron.
Pot Lid Handle
The handle on a pot lid does not need to be kashered for normal use during the year. 
Reason It does not normally get hot.
However, the pot lid handle must be removed and the lid cleaned where the handle attaches, if possible.
Note If the gap between the handle and lid cannot be completely cleaned, you may not use that lid for Passover and you normally may not kasher it if it becomes non-kosher. If the lid handle cannot be removed, consult a rabbi.

Pot or Pan Handle
A plastic handle that gets hot, especially if it is over a flame on a burner, may not be kashered. If the handle becomes non-kosher, it must be replaced. If a plastic handle connects directly to the metal of the utensil, consult a rabbi about what to do.
Food Nullification: Heat-Kashering
Three Methods of Heat-Kashering
Heat-Kashering is of three types:  Libun, Hag'ala, and Eruy Rotchim.
  1. Libun (Direct Heat)
    How It Works  Burns up any residual food taste
 What It Works On
Complete Burning (Libun gamur --heating metal red-hot).  Stoves, ovens, grills, grates, baking pans, roasting pans, etc., that were ever used with direct heat MUST be kashered by heating to red-hot (libun gamur). Libun gamur works on anything except pottery (this is a rabbinic injunction since you might not do a good job).
Light Burning (Libun kal--heating metal hot enough to burn paper on the side opposite the one being heated).  You may use this method whenever there is a question of whether an item needs libun. For example, food may have overflowed onto gas-stove grates. Due to safek, we use libun kal-- gas-stove grates do not need libun gamur.
Libun Gamur The entire metal substance of a utensil, oven, or other cooking surface becomes red hot, but the item does not need to be red hot all at the same time: it may be heated sequentially as long as the entire surface gets red hot at some time. Libun gamur can be done by blowtorch or by placing the item in a kiln. 
Libun Kal
  • Direct a flame, such as a blowtorch, onto the inside of a pot. Pot is hot enough when a piece of paper that touches the outside of the utensil burns (it does not need to burst into flame, just to smolder), or
  • Put the pot into the oven at 500 ° F for 40 minutes. (First, remove any non-metal handles; they will need to be kashered separately or not used.)
   Waiting Time  You do not need to wait at all before kashering by libun--and certainly not the 24 hours needed before kashering by hag'ala.
  1. Hag'ala (Boiling)
How It Works
Any non-kosher or meat or milk taste is removed from the walls of the utensil during boiling (hag'ala). You may kasher a pot or utensil by either:
  • Boil Method Boiling water within the pot to be kashered, and making the boiling water overflow, or
  • Dip Method Dipping a smaller pot or utensil to be kashered into a larger pot of boiling water.
What It Works On   
Pots and utensils that are used with liquids (meaning, liquid all the time) can be kashered by being immersed in boiling water (hag'ala). The utensil being kashered by hag'ala must be made of a material that can release flavor, such as metal or wood. Materials that cannot be kashered (except in a glazing furnace!) are pottery--and, by extension--china, enamel, and similar materials. 
Note  The Boil Method only helps if the utensil became non-kosher due to food inside the utensil. If the non-kosher food was on the outside of the utensil, you may only kasher it by the Dip Method or by libun kal.
Note The boiling water must reach at least the same temperature during kashering as when the utensil became non-kosher.
Note Once the Passover holiday has begun, chametz cannot be nullified with hot water/hag'ala (only libun can kasher something during Passover). You may only kasher during chol hamoed, not during the first and last (festival) days.
Note Whenever hag'ala is effective, you may instead use libun kal, since libun kal is a stronger form of kashering. Sometimes you may find it more convenient to use libun kal to kasher an item that needs only hag'ala.
Situation A metal pot of the opposite gender went through a dishwasher cleaning.
What To Do Even though the pot only needs hag'ala, you may instead kasher it by libun kal by putting it in an oven at 500° F (for this application).

The Boil Method can be used as:
  • Batel BaShishim ("nullifying in 60 times" the volume), or
  • Batel BaRov ("nullifying in a majority"--that is, boiling the item in water that is more than twice the volume but less than 60 times the volume of the non-kosher element).
NoteIf a pot is hot (over 120° F, or 49° C) when only part of the pot becomes non-kosher, the entire pot is non-kosher and its volume is figured into the volume of water needed for boiling.
NoteFor whether the lid becomes non-kosher, consult a rabbi.

In Batel BaShishim, by the actual halacha, you do not need to wait at all before kashering. But the custom is to wait 24 hours--except in extreme circumstances--because it is too hard to figure out 1/60th. In Batel BaRov, you must wait 24 hours.
The Boil Method: Batel BaShishim
Using batel ba'shishim for the Boil Method is not customary.  You may use it for emergencies ONLY; ask a rabbi in this case.
Example To kasher a spoon with the batel ba'shishim type of hag'ala, immerse the spoon in boiling water of a volume at least the volume of 60 spoons. No waiting is needed before kashering with this method.
The Boil Method: Batel BaRov
To kasher a pot or utensil by hag'ala using batel ba'rov:
  • Clean the pot or utensil well.
  • Wait 24 hours after the pot or utensil was last heated to more than 120° F, or 49° C (such as when it was cleaned).
Reason Waiting 24 hours allows the taste to become “ruined” and then to be nullified (batel) in a majority (ba'rov) of boiling water.
Note During the 24-hour waiting period, you could still “use” the utensil for watering plants, etc., as long as the water remains under 120° F.
  • Fill the pot to the brim with water.
  • Bring the water in the pot to a boil.
  • Cause the water to overflow the entire rim of the pot by:
    • Plunging something hot into the pot (any item that will not cause the water to stop boiling is OK), or
    • Tilting the pot to slosh water over all of the pot's rim.
  • Cool off the pot by dipping it in cold water or putting it under cold running water.
Note If you did not put the utensil under cold water, it is still kosher b'di'avad.
The Dip Method
To kasher a smaller pot or any other kasherable cooking or eating utensil by hag'ala, you may dip the pot or utensil into a large, kashered pot containing boiling water.
  • If the pot in which you are kashering the items had been heated to 120° F (49° C), with food of that gender in the pot, or more within the previous 24 hours, the items you are kashering will assume the gender of the pot.
  • If the pot in which you are kashering the items had NOT been heated to 120° F or more for at least 24 hours, any items that are kashered in it will become kosher and pareve.
Note When kashering a utensil by hagala, you may dip it into boiling water one part at a time; that is, you do not need to immerse the entire utensil under the water all at the same time. This is different from doing tevila since for tevila, the entire utensil must be immersed completely.
Calculating 24-Hour Waiting Time
Once a pot has become non-kosher due to any reason, if it gets heated to 120° F (49° C) or more with any food or liquid in it, you must wait another 24 hours from the latest heating before you can kasher it, since everything inside the utensil becomes non-kosher again.
Calculating Volume
If only part of a pot becomes non-kosher, as long as the pot was hot (over 120° F, or 49° C), the entire pot becomes non-kosher and its volume gets figured into the volume of water needed for boiling.
  1. Eruy Rotchim (Hot-Water Pour)
Process  Pouring hot water over, for example, a sink to kasher it.
Waiting Time You must wait 24 hours before kashering by eruy rotchim.
Note Only items that became non-kosher by being poured onto, may be kashered via eruy rotchim.
Note Smooth-surfaced wood may be kashered through eruy rotchim (pouring boiling water) but ONLY if it became non-kosher through eruy. If it became non-kosher by being cooked or heated in an oven, it may not be kashered via eruy rotchim.
Note A wooden cutting board may be kashered if the board is smooth. If it has cracks and crevices, it can be sanded until smooth and then kashered.

Food Nullification: Meluy V'Eruy
Meluy V'Eruy To Kasher Glass
Halachically, “glass” includes Arcoroc, Corelle, crystal, Duralex, and Pyrex.
NOTE In pre-war Europe, where glass was expensive and hard to obtain, it was customary to kasher drinking glasses, especially for Passover, by soaking the glasses for three 24-hour periods (meluy v'eruy), as follows:
Step 1: Submerge glasses in cold water for 24 hours.
Step 2: Empty water, refill, and submerge glasses again.
Step 3: Repeat Step 2.
NOTE If any of these materials were heated directly on a flame or other heat source, they cannot be kashered by meluy v'eruy!

Non-Jewish Cooks (Bishul Akum)
Bishul Akum: Prestigious Cooked Foods
Do not eat bishul akum (foods cooked by non-Jews under these conditions):
  • Prestigious, which a king or president of a country might serve at a state meal. (Foods that would not be served at a wedding are certainly not subject to bishul akum.)
  • Foods cooked in a regular stove/oven.
  • Foods that are only eaten cooked, such as:
    • Asparagus;
    • Eggs;
    • Some types of fish (not those eaten raw); and
    • Meat.
Foods that are sometimes or usually eaten raw are not subject to bishul akum, but they must be edible raw, without any further preparation.
  • All fruits.
  • Many vegetables.
Note For a food to be considered edible raw, more than 10% of the population near where you are must eat that food raw. Even if that food is eaten raw by most of the people in another country, you may only consider the people in your own locale.
Example Even though Japanese eat a lot of fish raw, only Jews living in Japan may consider raw fish free of bishul akum restrictions.
Note Ceviche, cold smoked salmon (lox), and foods that have been marinated or soaked in brine, vinegar, or other liquids are not considered to have been cooked and are permitted to be eaten even if wholly prepared by non-Jews, but not if the foods are cooked.
For a Jew to eat prestigious, “only-eaten-cooked” foods cooked by non-Jews, a Jew must do some part of the cooking—such as lighting a flame or participating in the cooking.
Note Bishul akum laws do not apply to foods cooked in a microwave oven or induction coil cooker.
Kashrut: Animals
Kashrut: Animals: Concepts: Masoret
Beheimot Do Not Need Masoret
Beheimot (4-legged kosher animals) do not need masoret (tradition passed from previous generations that something was kosher) to be identified as kosher; they just need to have split hooves and to chew their cud.
Fowl Must Have Masoret
Fowl must have masoret to be identified as kosher.
Kashrut: Dairy
Kashrut: Common Milk
Kashrut: Dairy: Common Milk (Chalav Stam)
For milk to be kosher, it must come from a kosher animal. You may use common milk (milk sold in conventional food stores without any kosher supervision) in the US.
Reason The US government enforces laws that permit only cow's milk to be sold as common milk.
Note If a country does not have such laws or does not strictly enforce them, you may not rely on that leniency and may only use milk supervised by Jews (chalav Yisrael).
Note Some people drink only chalav Yisrael milk even in the US.
Kashrut: Dairy: Chalav Yisrael

Chalav Yisrael is milk or milk products for which the milking was supervised by a religious Jew. Chalav Yisrael applies to milk, cream, and milk solids/dried milk. The only milk derivatives that are not subject to restrictions of chalav Yisrael are whey and cheese. But they must still be kosher.

Note Cooking kosher, non-chalav Yisrael dairy foods does not render the utensil non-kosher, even for someone who only eats chalav Yisrael.

Kashrut: Cheese
Kashrut: Cheese: Jew at Time of Rennet
Cheese/Gvinas Akum
Gvinas akum is cheese which has been made by non-Jews and by rabbinical prohibition is only kosher if a Jew was present during the cheese making OR if a Jew put the rennet into the milk.
Note If a Jew owns the milk before processing, a non-Jew can add kosher rennet as long as it can be confirmed that the rennet is kosher, even if no Jew is present during the cheese making.
Origin of the Problem: Chazal were concerned that the rennet used to make cheese might be from a non-kosher animal or even from a kosher animal that had not been slaughtered properly. Shulchan aruch says that even cheese curdled by kosher plant enzymes (such as fig branch sap or substances from certain thistle plants) are subject to the takana.
Note Gvinas Akum is not related to chalav yisrael; they are separate halachot.

Note Even rennet-less cheeses need hashgacha (religious supervision), but some non-hard cheeses may be an exception. Ask a rabbi.
Kashrut: Cheese: Microbial Enzymes
Cheese that is made using even microbial enzymes requires kosher supervision.
Kashrut: Dairy/Meat
Kashrut: Dairy/Meat
See Kashrut: Dairy/Meat Combinations.
Kashrut: Eggs
Kashrut: Eggs: Blood Spots: Unfertilized/Fertilized
Blood spots even from unfertilized eggs may not be eaten; the custom is not to eat that entire egg. Blood spots in fertilized eggs render the entire egg non-kosher.
Kashrut: Eggs: Few or Even Numbers
You may eat even numbers of food items.
Note Some people don't cook one or two eggs by themselves, but there is no problem with doing so.
Kashrut: Eggs: Hard-Boiling in Non-Kosher Pot
Do not eat hard-boiled eggs cooked in a non-kosher pot.
Kashrut: Fish
Kashrut: Fish: Buying in Non-Kosher Store
To Buy Fresh Kosher Fish in Non-Kosher Store
To buy fresh kosher fish in a non-kosher store:
  • If the fish is whole and has scales, it is kosher and you may buy it as it is.
  • If the fish has already been cut, skinned, and/or filleted and there are no non-kosher fish in the store, you may buy it as kosher.
  • If you want to have the fish cut, skinned, and/or filleted and there are non-kosher fish in the store, have the counter-person wash off the cutting board and knife with soap and water before preparing the fish and you may buy the fish as kosher.
  • If the fish has already been cut (and there are non-kosher fish in the store such that there might have been non-kosher fish oil on the knife or cutting board), just scrape off a tiny layer from the cut surface of the fish.
Note You may eat a skinned fish that you can positively identify from the flesh as kosher.
Example ALL salmon are kosher and may be eaten if they can be identified. 
Note You may not rely on the statement of a non-Jewish-owned store that the fish is kosher or is of a variety that you know to be kosher.
Kashrut: Fish: Varieties
Conger Eel with Scales
Conger eel with scales is a kosher fish! It must have a backbone.
Kashrut: Fish: Smoked
Kashrut: Smoked Fish
Smoked fish needs supervision due to possibly non-kosher items:
  • Brine in which the fish are soaked,
  • Hooks from which the fish are hung.
Kashrut: Fish/Dairy
Kashrut: Fish: Dairy and Fish Together
You may cook and/or eat dairy-containing and fish-containing foods together. Sefardim do not eat dairy and fish together.
Kashrut: Fish/Meat
Kashrut: Fish: Fish and Meat Together
Do not cook or eat meat-containing and fish-containing foods together:
  • After eating fish, you must eat and drink some other food before eating meat-containing food.
  • After eating meat-containing food, you must eat and drink some other food before eating fish.
Note If meat and fish were mixed or cooked together, there is no need to kasher the utensils.
Kashrut and Worcestershire Sauce
You may use and eat Worcestershire sauce on meat if the fish component is batel ba'shishim (nullified by being less than 1/60th of the total volume).
Kashrut: Meat
Kashrut: Meat: Blood
Introduction to Blood in Meat
Introduction to Blood in Meat
Status of Blood in Meat
Blood is generally forbidden to be eaten. However:
  • Blood that has not moved from where it was in the animal before the animal was killed may be eaten--but only if eaten raw.
  • Blood in veins and arteries may not be eaten.  If meat is cooked with this blood still inside the meat, the meat is non-kosher. (During kosher butchering, the main veins and arteries are removed.)
  • Capillary blood is permitted once the animal is dead. 
  • After meat has been salted, even if pink liquid comes out, the meat is still kosher.
Kashering Meat by Broiling after Three Days
Normally, meat must be soaked and salted within three days of being slaughtered.
REASON The blood may have solidified by then and will not be completely removed by salting. If you were to cook such meat, the blood would move and the meat would become non-kosher.
But, even after three days, you may broil or grill and then EAT the meat, as broiling forces out any blood that will come out. But you may not then COOK it afterward.
NOTEThere is no time limit for broiling the meat and making it kosher if done this way, but consult a rabbi for such cases.
Kashrut: Meat: Non-Glatt
Non-Glatt Meat for Sefardi Guest
Non-glatt meat at an Ashkenazi house doesn't necessarily render the food non-kosher for a Sefardi guest.
Non-Glatt Meat Utensils
Cooking kosher, non-glatt meat in a utensil does not render that utensil non-kosher, even for someone who only eats glatt meat.
Kashrut: Meat: Hindquarter
Hindquarter Meat
You may eat hindquarter if the sciatic nerve and forbidden fat are properly removed from a kosher animal that has been properly slaughtered.
Kashrut: Dairy/Meat Combinations
Introduction to Kashrut: Dairy/Meat
No Eating, Cooking, or Benefiting from Dairy with Meat
You may not cook or eat dairy and meat foods together, even when they are individually kosher.  You may not even derive any benefit from their being cooked together.
Kashrut: Dairy/Meat: Time Separations
Kashrut: Dairy/Meat: Waiting between Eating
Kashrut: Dairy/Meat: Waiting between Eating: Dairy after Meat
You may not eat dairy-containing foods directly after eating meat-containing foods, for two reasons:
  • So as not to have meat stuck in your teeth when you eat milk-containing foods.
  • So as not to eat dairy foods while you still can detect the taste of the meat-containing foods in your system.
Note There are various customs on how long to wait after eating meat-containing foods to eat dairy-containing foods, including:
  • 60 minutes for Jews whose families originated in Holland.
  • 3 hours for Jews whose families originated in Germany.
  • 6 hours for most other Jews, with variations including 5 hours-1 minute, 5 hours-31 minutes, and 6 hours.
Note You do not need to restart the waiting period if you burp up meat long after you eat it.
Kashrut: Dairy/Meat: Waiting between Eating: Meat after Dairy
To eat meat-containing food after eating dairy food:
  • Wait half an hour, or
  • You must:
    • Drink (or rinse your mouth with) some neutral/pareve beverage, and
    • Eat some neutral/pareve solid food.
Reason There may still be some dairy remaining in your mouth.
Kashrut: Dairy/Meat: Waiting between Eating: Neutral/Pareve D or DE after Meat
If you can definitively ascertain that a food is or is not dairy from the ingredient list, you may rely on it.
However, many food additives or ingredients that are dairy do not contain the word “milk" or “dairy” (for example, dairy-based flavorings or dairy derivatives such as whey or casein/sodium caseinate).
Situation Neutral/pareve food marked “D” or “DE” (“dairy equipment”) has no dairy ingredients (or the dairy ingredients constitute less than 1/60 of the food's volume.)
Note This does not get measured by weight.
What To Do You may eat the food:
  • Immediately after eating meat foods, but
  • Not together with the meat food.
Situation Genuine dairy constitutes more than 1/60th of the volume of the processed food.
What To Do You may not eat the food with, or immediately after, the meat food.

Kashrut: Dairy/Meat: Waiting between Eating: Bread with Dairy, Then Meat
Situation You said ha'motzi over bread for a dairy meal.
Status You may not reuse the same bread for a meat-containing meal. 
What To Do You may either:
  • Get some new bread, or
  • Not eat bread at all with the meat.
Note There is no need to say birkat ha'mazon after the milk-containing food and then say ha'motzi (or other fore-blessings) before eating the meat-containing foods.
Kashrut: Dairy/Meat: Waiting between Eating: Putting Dairy/Meat in Mouth
Situation You put into your mouth any amount of meat--even if you didn't swallow it or if you spit it out.
Status You may not consume dairy foods soon afterward. 
What To Do You must wait as usual (6 hours, or whatever your custom is between eating meat and dairy).
Kashrut: Dairy/Meat: Waiting between Eating: Parmesan Cheese
Situation You eat Parmesan cheese.
Status Before eating meat, you must wait six hours (or whatever is your custom to wait between eating meat and dairy).
Note Parmesan cheese is the only commonly available cheese that is considered hard enough to require waiting six hours after eating it before you eat meat-containing foods.
Note Parmesan cheese requires this waiting period even when the cheese is finely ground or is melted on pizza, mushrooms, or other foods.
Kashrut: Dairy/Meat: Waiting between Eating: Children
Children of any age, even babies, should wait one hour between eating dairy and meat-containing foods, unless there are health reasons not to wait.
From gil chinuch, children should wait 6 hours (or however long it is your custom to wait) between eating meat and dairy.
Kashrut: Dairy/Meat: Physical Separations
Kashrut: Dairy/Meat: Physical Separations: Dairy and Meat on Table
Situation Two eat at the same table, one person is eating dairy and the other, meat.
What To Do Separate the dairy and meat-containing foods using separate placemats or any type of physical barrier.
Note You do not need to use a separator if the people at the table are strangers to each other; the separation is needed only if they know each other from before.
Reason Separation serves as a reminder not to eat the opposite-gender food.
Kashrut: Dairy/Meat: Physical Separations: Washing Hands between Dairy and Meat
Situation You drank milk or ate solid dairy foods (such as cheese) and now want to touch and eat meat-containing foods.
What To Do
  • Milk
    You do not need to wash your hands after drinking milk unless you actually touched the milk liquid.
  • Solid Dairy
    You must wash your hands after eating solid dairy foods.
Reason Your hands likely had some contact with the solid dairy.
Kashrut: Dairy/Meat: Leniencies for Errors
Asking a Halachic Authority about Dairy/Meat Errors
The halachic category of dairy and meat errors, while extremely complicated, has many conditions for which leniency may be applied. Here are the main points a halachic authority (posek) will need to know:
  • Was the food or utensil hotter than 120° F (49° C)?
  • Had the utensil been used for hot food (over 120° F) within 24 hours?
  • How much food was involved?
  • What was the relative volume or quantity of the food and utensils? (1/60th of relevant volumes?)
  • How much food is normally cooked in the utensils?
  • Of what materials are the utensils made?
  • Was the food spicy (hot peppers, garlic, onions, lemon...)?
  • Was the food needed for Shabbat meals?
  • How much does the food cost?
Kashrut: Dairy/Meat: Ovens
Kashrut: Dairy/Meat: Baking Neutral/Pareve Foods in Dairy/Meat Pan
Kashrut: Dairy/Meat: Neutral/Pareve Foods in Clean Dairy or Meat Pan
Situation You cooked pareve food in a clean meat (or dairy) utensil.
What To Do
  • You may eat dairy-containing (or meat-containing) food immediately afterward.
  • You may not eat the food on a plate or utensil of the opposite gender.
  • You may certainly not eat it WITH opposite-gender food.
Note There is no difference whether the utensil had been used at 120° F (49° C) or more within 24 hours or not.
Kashrut: Dairy/Meat: Neutral/Pareve Foods in Dirty Dairy or Meat Pan
Situation You want to bake neutral/pareve food in a meat pan that has some meat liquid in the bottom.
What To Do You must use a double layer of separation such as foil, or else the pareve food will become meat (even if there is one layer of foil between the pareve food and the meat liquid).
Kashrut: Dairy/Meat: Baking at Same Time
Introduction to Kashrut: Dairy/Meat: Baking at Same Time
Introduction to Kashrut: Dairy/Meat: Baking at Same Time
Five factors affect cooking separate pans of dairy and meat in an oven at the same time (these are all b'di'avad cases):
  • Covered 
  Is either pan (or both) covered?
  • Outside Clean and Dry
  Are both pans clean and dry on the outside?
  • Food Non-Liquid (“Solid”) 
  Are the contents of one or both of them non-liquid (solid before OR after cooking
  OR both)?  That is, one or both are non-liquid (“solid”) at:
  • The beginning of the cooking,
  • The end of the cooking, OR
  • Both beginning and end of cooking.
  • Pans Touching 
  Are the pans touching?
  • Spicy/Charif
  Are the contents spicy/charif?
Kashrut: Dairy/Meat: Baking at Same Time: Definition of Terms
  • “Solid,” or “non-liquid,” means food is solid before OR after cooking--or both.
  • “Covered” means pan has at least a single cover; does not need to be sealed or double wrapped.
Kashrut: Dairy/Meat: Baking at Same Time: Solid, COVERED
L'chatchila: Do not bake separate pans—whether uncovered or not—of dairy food and meat food in the oven at the same time.
Reason The food might spill over.
B'di'avad, you may cook pans of dairy food and meat food at the same time in one oven if both are:
  • Not touching,
  • Covered, AND
  • Non-liquid; i.e., either:
    • Solid, or
    • Liquid only at the beginning or end of the cooking (but not both beginning and end).


Kashrut: Dairy/Meat: Baking at Same Time: Solid, UNCOVERED
L'chatchila, you should not bake uncovered dairy and meat foods in the same oven at the same time, even if both pans:
  • Are non-liquid, AND
  • Do not touch each other.
B'di'avad, both uncovered pans remain koshereven if they touch each other, if both pans:
  • Are non-liquid,
  • Are clean and dry (on the outside), AND
  • Do not contain spicy/charif food.
  • Food in both pans is solid.
  • One pan is covered, one pan is uncovered.
  • Both pans are clean and dry on outside. 
  • No spicy/charif.
Status They are both kosher b'dia'vad.
Kashrut: Dairy/Meat: Baking at Same Time: Liquid, UNCOVERED
Situation Two uncovered pans of food—one dairy, one meat—are baked at the same time in an oven. The contents of both pans are liquid (liquid before AND after cooking; even if not spicy).
Status They are both non-kosher, even if one pan is covered (but consult a rabbi for possible leniencies).

Situation Two pans—one dairy, one meat—bake at same time in same oven:
  • One is covered and contains liquid (even if not spicy);
  • One is not covered and contains solid food.
Status They are both kosher.

Situation Two pans—one dairy, one meat—bake at same time in same oven:
  • One is covered and contains solid food.
  • One is not covered and contains liquid (even if not spicy).
Status They are both non-kosher.
Kashrut: Dairy/Meat: Baking at Same Time: Both UNCOVERED and SPICY/Charif
Situation The food in two uncovered pans (one of dairy food, one of meat) baked in an oven at the same time is spicy/charif.
Status The food and utensils all become non-kosher, even if the:
  • Pans are clean and dry,
  • Pans are not touching, AND
  • Food is non-liquid.
Kashrut: Dairy/Meat: Baking at Same Time: Both UNCOVERED; One Is Spicy/Charif
Situation Two uncovered pans (one of dairy food, one of meat) are baked in the same oven at same time. The food in only one of them is spicy/charifEven if the:
  • Pans are clean and dry,
  • Pans are not touching, and
  • Food is non-liquid.
Status The spicy/charif one is b'di'avad kosher;
The non-spicy utensil and its contents are not kosher.
Kashrut: Dairy/Meat: Baking Consecutively
Baking COVERED/UNCOVERED Dairy and Meat Consecutively
Situation You cooked food of both genders:
  • In a clean oven,
  • In separate utensils,
  • UNCOVERED but consecutively (even within 24 hours).
    Note The first food must be removed before the second one is put into the oven.
  • If one or both are solid (non-liquid) at either the beginning OR end of the cooking OR both beginning and end:
They are both kosher; both food and pan.
  • If they were both liquid:
The second one is probably not kosher (both food and pan), but consult a rabbi.
  • If both are covered, they are both kosher.
  • If the first one to be cooked was covered, they are both kosher
  • If the first one was uncovered, they may both have become non-kosher--consult a rabbi.
Kashrut: Dairy/Meat: Oven Spills
Baking Opposite Gender in Oven with Spills
Situation One gender of food spills in an oven. You later heat utensils and food of the opposite gender in that oven to 120° F (49° C) or more.
Status The utensils and food may become non-kosher, due to the residue's vapor.
What To Do Consult a rabbi.
Note This applies whether the oven is kosher or non-kosher, the residue is dry or liquid, or the utensils or food later placed in the oven are covered or not covered.
Kashrut: Dairy/Meat: With Neutral/Pareve
Dairy/Meat with Neutral/Pareve Pot or Pan
Eating Dairy or Meat Cooked in Neutral/Pareve Pot or Pan
If you ate meat, you may then eat neutral/pareve food cooked in a clean dairy pan, even if the dairy pan was used at 120° F (49° C) or more within 24 hours.
Baking Neutral/Pareve and Dairy (or Meat) at Same Time
Baking Non-Liquid Neutral/Pareve and Non-Liquid Dairy (or Meat) at Same Time
Situation You bake non-liquid dairy food and non-liquid neutral/pareve food in one oven at the same time.
  • You may not eat the pareve food with meat food (and certainly not dairy food with the meat!), but
  • The utensil (pan) of the pareve food does not become dairy.
Note The same applies if you cook non-liquid meat with non-liquid pareve food.
Note If one or both of the foods were liquid, the utensil might be non-kosher. Consult a rabbi.

Baking Challa at Same Time as Chicken without Sauce
Situation You baked challa with chicken, both uncovered, in the same oven (the chicken had no sauce).
  • You may not eat that challa with dairy food, but
  • You do not need to wait another 3-6 hours after eating the challa before eating dairy.
Baking Challa at Same Time as Chicken with Sauce
Situation You baked challa with chicken, both uncovered, in the same oven (the chicken DID have sauce).
Status The challa becomes non-kosher even if the sauce was dry by the end of cooking.
Reason A rabbinic enactment requires that challa be pareve, lest someone eat it with the opposite gender food.  Consult a rabbi for exceptions. 
Note The rabbinic enactment applies to all bread, unless it looks different from normal bread or is small enough to eat at one meal.
Kashrut: Dairy/Meat: Soaked Together
Kashrut: Dairy/Meat: Soaked Together
For different genders of food being soaked together, see Taste Transfer: Soaking.
Kashrut: Dairy/Meat: Stovetop Spatters
Kashrut: Dairy/Meat: What Is a Spatter
Kashrut: Dairy/Meat: What Is a Spatter
A spatter is single drops of a substance.
Note In this website, a small spatter is a single drop and a large spatter is several or more drops.
Kashrut: Dairy/Meat: Spatter Temperature
Kashrut: Dairy/Meat: Spatter Temperature
You may assume that a spatter of single drops is less than 120° F (49° C) when it contacts a cold utensil or other food.
Kashrut: Dairy/Meat: Pot Spatters ONTO Utensil or Empty Pot
Kashrut: Dairy/Meat: Pot Spatters: Outside of Utensil, Below Normal Food Line
Situation A hot or cold meat utensil is empty or contains meat food. It receives a spatter of dairy below the normal food line and the spatter is less 1/60th of the volume of the pot.
  • The food in the utensil (if any) is kosher in all cases.
  • Pot is kosher after 24 hours without kashering.
What To Do You must wash the pot off with cold water and soap.
Kashrut: Dairy/Meat: Tiny Pot Spatters: Outside of Utensil, Above Normal Food Line
  • The outside of a hot, empty pot of one gender gets a spatter of opposite-gender food ABOVE the normal food line. 
  • The spatter is less than 1/3600 of the normally used volume of the pot (instead of the normal criterion of 1/60th of the volume--this being 1/60th of 1/60th).
Status The pot is kosher after 24 hours without kashering.
What To Do You must wash the pot off with cold water and soap.
Note This applies even if the pot had been used at 120° F (49° C) or more within 24 hours.
Kashrut: Dairy/Meat: Larger Pot Spatters above Normal Food Line
  • A hot, empty pot of one gender gets a spatter of opposite-gender food ABOVE the normal food line. 
  • The spatter is more than 1/3600 of the normally used volume of the pot.
Status The pot is non-kosher.
What To Do You must kasher the pot by washing in cold water and soap, waiting 24 hours, and then boiling the pot.
Kashrut: Dairy/Meat: Pot Spatters and Pareve
  • Food of one gender spatters onto the outside of a pareve utensil. 
  • Either the food and/or the utensil are hot.
Note If the pot is not hot, a small spatter will not be hot.  If the spatter is large (more than one drop), the spatter may be hot. Ask a rabbi what to do.
Status The utensil assumes the spatter's gender UNLESS the spatter was less than 1/60th of the volume of the metal in the pareve utensil (not 1/60th of the volume the container usually holds). Consult a rabbi.

Kashrut: Dairy/Meat: Spatters INTO a Pot of Food
Kashrut: Dairy/Meat: Hot Dairy Food Spatters INTO Meat Pot, or Vice Versa
  • Hot dairy food spatters INTO a pot of meat food, or vice versa.
  • Spatter is less than 1/60th of the volume of the food into which it spattered.
Status The spattered food is nullified (batel ba'shishim).
What To Do As there is nothing to wash off, the food may be eaten, but you should remove the spattered food, if possible. The pot is kosher.

Kashrut: Dairy/Meat: Stovetop Spills
Kashrut: Dairy/Meat: Spills and Opposite Gender Utensil
Kashrut: Dairy/Meat: Hot Spills and Opposite Gender Utensil: Unused
  • Hot food of one gender spills (falls into or onto) an empty utensil of the opposite gender.
  • The utensil was unused at 120° F (49° C) or more for at least 24 hours.
  • The utensil is usually non-kosher.
  • The food is kosher.
Note If the spill is spicy/charif or if the utensil had been used hot within the 24 hours before the spill, consult a rabbi.

Kashrut: Dairy/Meat: Spills: Food onto Opposite Gender Utensil: Flow Chart
What to Do Wash off with cold water and soap.
Status Everything is kosher and may be used immediately.
Note Clean means no residual food, including pareve; this IS essential since the food or utensil or both were hot! If used at 120° F or more for pareve within 24 hours, ask a rabbi.
  • Food is kosher
  • Utensil requires kashering
What to Do
  • Wash utensil with cold water and soap.
  • Wait 24 hours after the spill occurred before kashering it.
Note If you wash off the utensil with hot (above 120° F) water, you must wait 24 hours after cleaning the utensil before kashering it.
IS THE SPILLED FOOD LESS THAN 1/60th of the volume of the commonly used capacity of the utensil (if the utensil is empty) OR less than 1/60th of the actual volume of food contained within the utensil?
  • Food is kosher.
  • Utensil is kosher after 24 hours.
What to Do Wash utensil with cold water and soap and wait 24 hours before using the utensil.
Note If utensil had food in it and the spilled food was less than 1/60th of the volume of the food in the utensil, you may use the utensil immediately after cleaning it and you do not need to wait 24 hours.
NO (Spilled food was 120° F or more, OR the utensil not clean, OR the utensil was used within 24 hours, and spilled food is more than 1/60th of the utensil's volume)
  • Food is non-kosher.
  • Utensil is non-kosher.
What to Do Utensil must be kashered.  See Hag'ala/Boiling or Libun/Direct Heat for instructions on how to kasher each material.

Utensil Chart
Utensil Chart
Dairy/Milk Food Falls into/onto Meat or Meat Falls into/onto Dairy/Milk Food

Status If you can separate them (there are no cracks in the meat), both foods are kosher.  Consult a rabbi.
What to Do
  • If one or both of the foods were already cooked, separate them and wash with soap and water (if possible).
  • If it is not possible to separate them, just cut off the thinnest slice possible from each surface of each food which had been in contact with the opposite gender food and you may use the food.
Status If both foods are cold and you can separate them (there are no cracks in the meat), they MAY be kosher.  Consult a rabbi.
  • Both foods are non-kosher if they cannot be separated.
  • If you can separate them enough that one becomes less than 1/60th the volume of the other:
    • The larger food is kosher.
    • The lesser one is non-kosher
What To Do
  • Once the two foods are separated, wash or otherwise remove the smaller food from the larger one.
  • If not possible, cut off the thinnest slice possible and you may eat the remaining food.
Note If there are cracks in raw or cooked meat, and if you can clean off enough of the dairy spill so that the remainder is less than 1/60th, it may be kosher--ask a rabbi.
Status Both liquid foods are non-kosher.
Exception If one liquid food is less than 1/60th the volume of the other one, the mixture is kosher.
Note If non-kosher wine is involved, see below.
Status If one (or both) of the foods is hotter than 120° F, both foods are non-kosher.
Exception If one food is less than 1/60th of the volume of the other:
  • The larger-volume food may be kosher (consult a rabbi).
  • The smaller-volume food remains not kosher.
Possible Exception  If the food on the bottom is cold and thick, consult a rabbi.

If either food is spicy, see above.
If any combination (solid and liquid; solid and solid which are in any liquid; or liquid and liquid) of dairy and meat were soaked together for 24 hours or more, even if cold, they are all not kosher.
Exception In any of these three cases, in which one is less than 1/60th the volume of the other:
  • The larger food is kosher.
  • The lesser one is non-kosher.
Note You must remove the smaller food from the larger one and wash off the larger one, if possible. If you don't know how long the foods soaked together but it may have been less than 24 hours, you may use the foods.
Accidental Mixtures of Dairy and Meat Foods
Accidental Mixtures of Dairy and Meat Foods
Kashrut: Dairy/Meat: Utensils
Kashrut: Dairy/Meat: Utensils: Dry/Wet
Kashrut: Dairy/Meat: Utensils: Heat with Dry/Wet
Hot, clean, dry utensils of opposite genders, even if touching each other, both remain kosher.
Hot, clean, wet utensils of opposite genders touching each other are both not kosher
SITUATION One of the utensils had not been used in less than 24 hours before the contact.
STATUS That unused utensil becomes not kosher. However, even if the other utensil had been used in less than 24 hours before the contact, it remains kosher.

Kashrut: Dairy/Meat: Other Useful Cases
Kashrut: Dairy/Meat: Condiments
Cold Condiments Used for Dairy and Meat
B'di'avad, you may scoop out mayonnaise or mustard and spread it on meat and then scoop out more and then later use same condiment on dairy foods (and the same for dairy and later on meat) as long as any residual food is less than 1/60th of the total volume of food. But the preferred practice is to have two separate containers, one for dairy and one for meat foods.
Kashrut: Dairy/Meat: Countertops
Kashrut: Dairy/Meat: Separate Countertops
Separate Dairy and Meat Countertops
Ideally, allot separate counter space for meat and dairy so they do not share the same space.  
Kashrut: Dairy/Meat: Taste Transfer in Countertops
Hot, Wet Taste Transfer in Countertops
A hot (120° F--49° C--or more), wet utensil transfers its gender to a countertop upon which it is placed, but only at the area of contact.
Status of Countertop
  1. Gender status of the countertop:
    • D'rabanan, the countertop area of contact remains that gender until kashered (as long as the countertop material is kasherable).
    • D'oraita, the countertop reverts to kosher-neutral/pareve after 24 hours.
    Note If the utensil and counter were not wet (nor dirty with food) at the area of contact, there is b'di'avad no transfer of gender.
  2. If you put a hot, wet utensil of the opposite gender on that same spot, that counter space may become non-kosher.
Status of Utensils
If the counter had not had a hot, wet utensil/container of food of the opposite gender placed on the same spot within 24 hours of each other, the utensils may be used and the utensils are still kosher.
Status of Food
This does not apply to food that is directly placed on the counter, in which case the food might become non-kosher.
Kashrut: Dairy/Meat: Cutting Boards
Kashrut: Dairy/Meat: Cutting Boards
Situation You cut a spicy/charif item of one gender on a cutting board (whether wood or plastic), and then cut the opposite-gender spicy/charif food on that same cutting board.
Status Generally, the board and the knife and whichever food was cut second becomes non-kosher. Consult a rabbi for exceptions.
What To Do If you can sand off the surface to below the level of any knife cuts, the board might be kosher. Consult a rabbi.
Kashrut: Dairy/Meat: Dishwashers
Kashrut: Dairy/Meat: Dishwashers: Intentional Mixing of Utensils
You may not intentionally put a pareve utensil in a dishwasher that contains dairy or meat dishes. If you do, the formerly pareve utensil will take the gender of the other dishes, unless it is of glass, Pyrex, or other materials that do not take on gender when in hot water.
Kashrut: Dairy/Meat: Dishwashers: Accidental Mix-up
Situation After washing a load of utensils of one gender in your dishwasher, you find an item of the opposite gender in your dishwasher.
  • The single item is non-kosher
  • The remaining items will most likely be kosher (as long as the single item is less than 1/60th of the total volume of items and water in the dishwasher).
Kashrut: Dairy/Meat: Dishwashers: Neutral/Pareve Item
You may not wash a neutral/ pareve dish in a meat or milk dishwasher--even if there are no dirty dishes with milk or meat on them and even if there are no other dishes in the dishwasher. If you did, the neutral/pareve dish may have become the gender of the dishwasher, but consult a rabbi for leniencies.
Situation You have a meat or milk dishwasher and you washed a neutral/pareve utensil in it.
What To Do If the dishwasher has dirty dishes containing milk or meat food, the neutral/pareve utensil will become that gender. However, if the dishwasher does not have any dirty dishes with food of either gender on them and the dishwasher has not been used for at least 24 hours, the pareve dish will remain pareve.
NoteThis is a b'di'avad (after the fact) case. You may not intentionally (l'chatchila) wash the pareve utensil in a gendered dishwasher.
Kashrut: Dairy/Meat: Drawers
Kashrut: Dairy/Meat: Drawers
Situation You find an eating or cooking utensil of one gender in a drawer of the opposite gender.
Status You may use the item without kashering it.
Kashrut: Dairy/Meat: Microwave Ovens
Kashrut: Dairy/Meat: Microwave Ovens
As with conventional ovens, these factors determine kosher/non-kosher status for a microwave oven:
  • Was it clean?
  • Did the interior surfaces get hot (120° F--49° C--or more)?
  • Was it used in the previous 24 hours?
Note Microwave ovens do not have the problems of bishul akum that conventional ovens have.
How To Check If a Microwave Oven Will Get Hot during Cooking
To determine if the walls of a microwave oven will get hot during cooking:
  • Boil water for as long as food would typically be cooked in that microwave oven, and
  • Touch the inside walls, floor, door, and ceiling
    • If the walls are too hot to touch, the walls may acquire the gender of any food cooked in the oven. (If the walls are already the opposite gender when cooking a food, the oven may become non-kosher.)
    • If the walls are not too hot to touch, then no change of status occurs.
Kashrut: Dairy/Meat: Microwave Oven Dishes
You may microwave a dairy food in a meat (or meat food in a dairy) glass (or Pyrex or Corelle) utensil. Even if the food gets hotter than 120 degrees, the food and utensil are still both kosher. (This is not true if placed in a conventional oven!)
Kashrut: Dairy/Meat: Pot Lids
Kashrut: Dairy/Meat: Pot Lids
Pot lids are treated as if they are utensils.
  • You put a lid of one gender on a pot of the opposite gender.
  • The pot is more than 120° F (49° C).
Status The lid becomes non-kosher and the pot and food inside usually will be non-kosher, but ask a rabbi about possible leniencies.
Kashrut: Dairy/Meat: Refrigerators
Refrigerators and Hot Pots of Dairy/Meat
Hot pots on a refrigerator shelf with pots of the opposite gender that touch each other are only a problem if wet. There is no problem if they are:
  • Both cold, or
  • Even if they are spicy.
Kashrut: Dairy/Meat: Sinks
Sink Racks and Dairy/Meat
Two racks or other utensils, one dairy and the other meat--that are used in a single sink (whether together or sequentially) may become non-kosher if they ever reach more than 120° F (49° C) while in the sink. Consult a rabbi.
Kashrut: Dairy/Meat: Sponges
Sponges and Dairy/Meat
Situation You inadvertently use a brush or sponge (hotter than 120° F--49° C) of one gender on a utensil of the opposite gender.
Status The sponge or brush becomes non-kosher, but ask a rabbi about the status of the utensil.
Kashrut: Dairy/Meat: Steam
Steam and Utensils of Dairy/Meat
Situation Steam of one gender touched a utensil of opposite gender.
What To Do  Ask a rabbi.
Kashrut: Dairy/Meat: Stovetop
Stovetop Surfaces: Kosher Status
A stovetop surface is likely to be non-kosher due to previous spills of both genders.
Reason The stovetop will have been heated to more than 120° F (49° C) from:
  • A large spill, and
  • Likely, from the oven below.
Stovetop Surfaces: Clean, Cold Utensil
Situation A dry, clean, cold utensil is put on a dry, clean, hot stovetop.
Status The utensil is kosher b'di'avad.
Stovetop Surfaces: Hot Utensil with Food
A hot (120° F--49° C--or more) lid or utensil (such as a spoon, fork, or ladle) containing food is put on a stovetop surface. Consider:
  • Temperature of stovetop;
  • Volume of food on lid or fork/spoon;
  • Timing--Was the stovetop used at 120° F or more within 24 hours? (If not and if it is clean, everything is kosher b'di'avad.)
Status of Utensil
  • Utensil: Dry.
 Stove: Clean.
 Utensil is kosher.
  • Utensil: Dry or wet.
 Stove: Dirty.
 Utensil is non-kosher.
  • Utensil: Wet.
 Stove (clean or dirty); had hot opposite-gender food on it within previous 24 hours.
 Utensil is not kosher.
  • Utensil: Dry or wet.
 Stove: Clean; no hot opposite-gender food on it within the previous 24 hours:
 Utensil is kosher.
Kashrut: Miscellaneous Items
Kashrut: Alcoholic Beverages
Pure Alcohol
Pure alcohol is kosher if not derived from any grapes or any other non-kosher source.
Fermented Fruit Juices
Kosher supervision is recommended for fermented non-grape fruit juices (apple cider or fermented pomegranate, cherry, etc.) even if they do not have any additives and contain only pure juice.
All beer in the USA is kosher and does not need supervision. Many beers in other countries are also kosher even without supervision, but the status should be checked with local kashrut authorities.
Situation Some beers have lactose added.
Status If the lactose is less than 1/60th of the total volume, the beer is not considered to be dairy.
The principal difference between kosher wine (or grape juice) and non-kosher wine (or grape juice) is that the kosher wine must be produced and handled only by religious Jews. However, once the wine or grape juice has been cooked (“mevushal”), it may be handled by anyone, including people who are not Jewish, and it will still remain kosher. Pasteurization may be sufficient to be considered “cooking” for this purpose.
Note Many good-quality wines are NOT mevushal and when those bottles are opened must not be handled by anyone who is not a shomer Shabbat Jew.
Almost all whiskies are kosher, but check the source to be certain.
Many liquers are kosher even without supervision, but many are not kosher and a reliable source should be checked before drinking any liquers.
Note Some liquers are kosher when produced or bottled in one country but are not kosher when produced in other countries.
Drinks from the Five Grains Owned by a Jew during Passover
All beverages that contain alcohol made from any of the five grains (wheat, barley, oats, rye, and spelt), and which were owned by a Jew during the Passover holiday, are not kosher.
Kashrut: Bread
Bread made in not-kosher bakeries can be assumed to be kosher ONLY if:
  1.  It has no ingredients other than flour, water, yeast, and salt. French baguettes and some other breads are OK, as are many breads baked in other countries of the same type.
  2.  It is baked on a hearth and not in a pan.
Note On a hearth, any non-kosher ingredients from other baked foods get burned up.
Kashrut: Lanolin
Lanolin Not Kosher
Lanolin is not kosher.
Kashrut: Manufacturing Aids
Why Simple Reading of Ingredients Not Enough
Even though foods manufactured and sold in the USA are required to list their ingredients, a simple reading of ingredients may not be sufficient to determine the kosher status of some foods because:
  • They are not required to list “manufacturing aids” such as oil, and
  • The manufacturing equipment may be non-kosher.
Kashrut: Mitts (Oven)
Separate Oven Mitts for Dairy and Meat
Use separate oven mitts for each gender.
Reason Oven mitts assume the gender of any hot food that spills on them. This could make them non-kosher and cause future utensils to become non-kosher.
Kashrut: Modified Substances
Modified Non-Kosher
A non-kosher substance becomes kosher once it is modified and no longer has the original taste.
Example Animal bones are burned for charcoal to filter cane sugar from molasses in order to make white sugar.  The bones are not only not non-kosher, they are pareve.
Note Rabbinic supervision is required to ensure that the bones have been completely burned. 
Kashrut: Nutritional Supplements
Kashrut and Non-Kosher Nutritional Supplements
If kosher supplements are not available or are not as good as the non-kosher ones, you may use non-kosher nutritional supplements, including non-kosher gelatin capsules:
  • If you are sick (disease, headaches, weakness....), or
  • To improve your health if you have deficient nutrition
Note You may not take non-kosher supplements to prevent disease.
Kashrut: Oil
Oils and Kashrut Supervision
You may not use vegetable oil that has been processed in non-kosher equipment.
Reason The main problem can arise from deodorization of the oil, which is done in hot vessels.
Virgin Olive Oil
Virgin and extra virgin olive oils (which have not been deodorized and still smell like olives) are usually kosher without needing supervision.
Note A hechsher is recommended anyway due to occasional adulteration.
Non-Olive Oil Oils
Other vegetable, nut, seed, and grain oils normally require kosher supervision to be considered kosher.
Note Oils that are cold-pressed, not deodorized, and still smell like their source-fruit or seed require kosher supervision because they may be filtered through the same filter as non-kosher oil.
Kashrut: Pet Food
Pet Food
Regular pet food is not asur b'hana'a except if it contains milk and meat that were cooked together. Pet food containing chametz is forbidden to be owned or used on Passover.
Kashrut: Soap
Kashrut: Non-Certified Soap
Soap must be considered non-kosher unless it is certified kosherSoap without kosher supervision should not l'chatchila be used on food utensils--even if you use cold water and even on glass--because a soap residue adheres to the surfaces, even after careful rinsing. 
Bar soap is generally made from animal fat. Since all soaps do have taste and might be edible by a dog, they might not be nifsal for a dog and therefore cannot be used on eating utensils.
Note However, a dish remains kosher b'di'avad if washed with cold water and non-kosher soap made from non-kosher fat.
Kashrut: Non-Certified Dishwashing Liquids/Powders
Dishwashing detergents may be assumed to be kosher unless known to be non-kosher.
Kashrut: Substances Not Swallowed
Non-Kosher Mouthwash
You may use non-kosher mouthwash, even if you may swallow some residual mouthwash, as long as you do not intend to swallow the mouthwash.
Note On Passover, you may not use chametz mouthwash.
Kashrut: Trivets
Trivets for Dairy and Meat
Use separate trivets for each gender.
Reason A trivet assumes the gender of any hot food that spills on it. This may make it non-kosher and cause future utensils to become non-kosher.
Kashrut: Plants
Kashrut: Plants: Bugs
Introduction to Kashrut: Plants: Bugs
Why Bugs May Not Be Eaten
Bugs are not kosher and may not be eaten for two main reasons:
  • First, the Torah forbids the “sheretz ha'shoreitz al ha'aretz” (“creeping thing that creeps on the ground”).
  • Second, if people consider bugs disgusting to eat, the bugs are forbidden.
               Note Eating a bug causes more infractions of halacha than eating pork!
General Rules: Kashrut and Bugs
Three basic principles govern bugs/insects in food:
  1. Partial-Bug Nullification
    A whole bug or insect cannot be nullified, even when it makes up less than 1/60th of the volume of the food in which it is found.
    Note Any bug that is missing even a tiny part of its body may be nullified if less than 1/60th of the volume of the food in which it is found, but only if:
    • You cannot remove the bug, and
    • You cannot see it. 
    Note If you can remove the bug, you must remove it.
  2. The Three-Bug Rule
    Any time you find three bugs in food, you must assume there are more bugs to be found and you must therefore check every piece of that food before eating any of it.
  3. The Still-Kosher Food-and-Pot Rule
    Even if the bugs were cooked in the food, as long as you later remove all the bugs, the food and the utensil in which they were cooked remain kosher.
    Exception If bugs make up 50% or more of the total volume, the food is not kosher.
    What To DoIn this case, you should consult a rabbi about whether the utensil is kosher.
Kashrut: Plants: Bugs: For What To Check
Kashrut: Plants: Bugs: For What To Check: Visibility
Invisible Organisms
You are not forbidden from eating any life form that cannot be seen with the naked eye, such as micro-organisms.
Checking Bugs by Normal Eyesight
When checking edible plants for bugs, only bugs that are visible to a person with normal eyesight may not be eaten.
Note If you have poor vision, you must have someone else do the checking or use a magnifier.
Kashrut: Plants: The Three-Bug Rules
Kashrut: Plants: Three-Bug Rules: Cooked Food
Introduction to Finding Three or More Bugs in Cooked Food
If you find three or more bugs cooked in otherwise kosher food, you must throw out the food, because you must assume that there are more bugs in the food and that the food is therefore not kosher.
Finding One or Two Bugs in Cooked Food
Situation You find one or two bugs in cooked food.
What To Do Just remove the bugs and eat the food.
Finding Bugs in Cooking Water
Situation You are cooking food and you find even three or more bugs floating in the cooking water.
What To Do You may simply pour out the bugs and continue cooking with the water and ingredients that were there, but ONLY if you are certain that there are no more bugs anywhere in the food in that utensil.
Kashrut: Plants: Three-Bug Rules: Raw Food
Three or More Bugs in Raw Food
Situation You find three or more bugs in raw food.
What To Do Go through all the food. If you can remove all bugs that are mixed in the food, you may eat the food.
Kashrut: Plants: Bugs: Which Foods To Check
Checking Fresh Vegetables Depending on Locale
Vegetables, herbs, and other edible plants that may have bugs must be checked only if those plants commonly have bugs in the locale in which they are grown.
Note Bug infestations vary from locale to locale where the vegetables were grown; even if bugs are a problem in one place, they may not be in others.
Note You must check all of that particular fruit or vegetable for bugs if there would commonly be a bug in 10% or more of samples.
Checking Triple-Washed Greens for Bugs
For vegetables that commonly have bugs in them, you must check even triple-washed lettuces and other greens, even if they have been cut and packaged, unless they have a hechsher stating that they have been checked.
Which Foods Commonly Have Bug Infestations
The most common foods with bug infestations are raw vegetables, but bugs may also infest grains, some fruits, spices, and nuts.
All Herbs Need Checking
Many fresh herbs might contain bugs and therefore must be checked before use.
Difficult-To-Check Vegetables
Eating closed vegetables from which bugs won't be washed out, such as artichokes and Brussels sprouts, is not recommended. 
Note For a way to use artichokes, see Checking Raw Artichokes for Bugs.
Checking Frozen Vegetables for Bugs
You may eat any and all frozen vegetables and you do not need to soak them first or check them for bugs since the manufacturer washes the vegetables to remove bugs before cooking. If, however, you do find bugs, don't eat the vegetables. Kosher supervision is recommended.
No Need To Check Most Frozen Fruits for Bugs
You may eat all frozen berries, except strawberries, without checking for bugs.
Kashrut: Plants: Bugs: How To Check
Kashrut: Plants: Bugs: How To Check Vegetables
Checking for Bugs If Bugs NOT Common
If Bugs NOT Common on That Plant Grown in That Area
If less than one bug is usually found in 10 servings, you may simply wash the vegetables and then use them. If you happen to find a bug, you must remove it and you do not need to check the others.
Note If you find three bugs, you must check all of the food.
Checking for Bugs If Bugs Are Common
If Bugs Are Common on That Plant Grown in That Area
The presence of insects on fruits, vegetables, grains, etc., depends on season, location, crop type, year, and current conditions in the growing area. If more than one bug is usually found in 10 servings, you must wash or soak (preferably in salt water or soapy water) all of the food and carefully check a quantity equal to three servings. You may check the food or the water in which the food was soaked, if such soaking will remove the bugs.
Note Soapy water may be required to remove all bugs.
If You Do Not Find Any Bugs
If you do not find any bugs by this procedure, you may use all of the other (uninspected) food.
If You Do Find Bugs
If you find even one bug, you must either check each piece of vegetable OR soak (preferably in salt water or soapy water) or rinse the entire batch. Then check three more servings and continue until no bugs have been found after one cycle of washing and inspecting.
Note You may keep washing vegetables multiple times, without limit, until there are no more bugs.
Checking for Bugs Using Chazaka
Checking for Bugs Using Chazaka
Soak vegetables (preferably in salt water or soapy water) and check three servings from same batch of vegetables. If you find no bugs, you may employ a chazaka to allow use of the remaining vegetables without checking them.
Kashrut: Plants: Bugs: How To Check Grains
Checking Grains for Bugs
To check grain for insects, spread the grains on a flat surface.
Kashrut: Plants: Bugs: Checking Individual Produce
Checking Raw Artichokes for Bugs
Artichokes frequently have bugs that cannot be washed out. To use artichokes, you must generally remove all the leaves before cooking.  You may then:
  • Just cook and eat the artichoke hearts, which infrequently have bugs, OR
  • Check all the leaves, remove any bugs, and then cook and eat the leaves. 
Note If you are preparing many artichokes, you could:
  • Remove the leaves of three artichokes,
  • Check all the leaves, and, if there are no bugs,
  • Cook and eat the remaining whole artichokes in that batch without removing the leaves.
Finding Bug in Cooked Artichoke
If you cook an artichoke and then find a bug in it, the entire artichoke is not kosher and may not be eaten, even if you cut away the part with the bug in it.
Reason We assume that there are more bugs inside.
Asparagus, whether fresh or frozen, is OK to eat:
  • Fresh Asparagus:  You must wash fresh asparagus and check for bugs.
  • Frozen Asparagus: You do not need to wash frozen asparagus.

Fresh broccoli must be soaked (preferably in a solution of chlorine in water) and the water checked until no bugs are found.

Note You may wash indefinitely until the bugs are gone.

Figs must be checked.
Reason Fig worms sometimes grow in the fruit while the fruit is still on the tree.
Note Worms may only be eaten if they grew in the fruit after it was picked and never came out (and even then, only if they are not considered disgusting).
You must check mushroom gills for bugs and you must remove them if present. 
Note This is normally not a problem in US-grown mushrooms but is a problem in mushrooms grown in China and other countries.
Parsley's bugs can be removed by hitting the parsley on a table, but you must still check the parsley after hitting.
Raspberries and other hollow berries: Blow into them to remove bugs.
Romaine can have green or black bugs, which must be removed.
Sea Vegetables
Sea Vegetables
Sea vegetables are OK whether raw/fresh, dried, or toasted, but you must check for small crustaceans and other sea life.
Spices (pure) are OK everywhere but beware of bugs. If the spices are ground, you may use them.
Reason Any bugs would be ground up and not visible.
Note Spices from China, even if ground, need a hechsher
Note Spices from Eretz Yisrael may have teruma or ma'aser issues.
Fresh spinach may have bugs and must be checked.
Frozen spinach does not need to be checked, especially if chopped.
Note Although chopped spinach may not be chopped finely enough to grind up very small bugs such as aphids, you may still eat the spinach.

To eat strawberries:

  • Cut off the green at the top, and

  • Soak the remaining strawberry in mildly soapy water.

Note This applies to fresh or frozen strawberries since bugs can burrow into the surface. (Defrost frozen strawberries before trying to remove bugs.)

Vinegar has “eels” in it during production, but the eels are typically filtered out and you may use the vinegar.
Kashrut: Grape Juice and Wine
Kashrut: Wine Supervision
When No Wine Mashgiach Needed
No mashgiach is needed if:
  • The owner of wine production and all of the workers are shomer Shabbat, and
  • No non-Jews or non-shomer Shabbat Jews come in contact with the wine or grape juice.
Kashrut: Uncooked Grape Juice/Wine
Kashrut: Open, Uncooked Wine: Drinking or Benefiting From
You may not DRINK or DERIVE ANY BENEFIT FROM open (unsealed), non-mevushal (uncooked, previously kosher) wine or grape juice that has been handled by:
  • A non-Jew, or
  • Any Jew who intentionally does not observe the laws of Shabbat.
Note Even though some people are not stringent about this, they should be since the prohibition is from the Talmud.
Note “Deriving benefit” includes that you may not sell it, feed it to an animal, etc.
Note There may be exceptions for cases involving large losses. A large loss is subjective to the individual's actual wealth and also to that person's perception of what is a large loss. Consult a rabbi.
Kashrut: Open, Uncooked Wine: From When May a Non-Observant Person Not Handle?
A non-Jew or non-shomer Shabbat Jew may not handle wine (or grape juice) once the juice has been separated from the lees (the remaining solid parts of the grapes).
Note Once ANY juice has been removed from the vat, all of the remaining grape juice or wine becomes subject to becoming non-kosher if contacted by anyone other than a shomer-Shabbat Jew.
Kashrut: Kilayim
Kashrut: Orla
Kashrut: Orla
See Orla.
Kashrut: Pat Akum
When You May Eat Pat Akum
You may eat bread that was not baked by Jews (pat akum) as long as you know that it is kosher or it was supervised as being kosher by a reliable source.
Kashrut: Yashan
Kashrut: Yashan
See Yashan.
Introduction to Kashering
Kashering: Burners
Kashering: Burners: Gas
Kashering a Gas Stove
To kasher a gas stove:
  • Remove the burner grates,
  • Clean off any deposits,
  • Place the grates on a clean surface inside the oven, and
  • Heat the grates to the oven's maximum temperature for 40 minutes.
Kashering: Burners: Electric
Kashering a Clean Electric Stove
To kasher a clean electric stove, turn the burners on to the highest setting until the burner glows red (this is easier to see at night) or until a piece of paper will burn on it (the paper does not need to burst into flame).
Kashering: Dishwashers
Kashering a Dishwasher from Non-Kosher to Kosher
Dishwashers may generally not be kashered except when made of stainless steel (and have no non-kasherable materials inside, such as plastic, silicone, or rubber).
Note If the racks are not stainless steel or if they are coated with plastic or other substances, they may not be kashered.
Kashering a Dishwasher from Dairy to Meat, or Vice Versa
You may not kasher a dishwasher (even if it is stainless steel) from dairy to meat, or vice versa, in order to use the dishwasher for dairy and for meat utensils, even sequentially.
Kashering: Grills
Kashering a Grill
Make a grill red hot to kasher it.
Kashering: Ovens
Kashering an Electric or Gas Self-Cleaning Oven
To kasher a self-cleaning electric or gas oven, you do not need to clean it first. Just run the self-clean cycle.
Kashering an Electric or Gas Regular Oven
To kasher an oven that is not self-cleaning, you must:
  • Remove any deposits on the walls, racks, and window.
    Note If there are stains or deposits, you must clean them off or burn them off. If the stains or deposits do not come off after two cycles of using strong oven cleaner such as Easy Off, the oven is considered sufficiently clean.
  • Turn the oven on to its maximum temperature for 40 minutes.
    Note Self-cleaning ovens attain a higher maximum temperature than do non-self-cleaning ovens.
Kashering Oven Racks

You may kasher oven racks by putting them in a self-cleaning oven and running the self-clean cycle. Or, clean with oven cleaner and then put into a normal oven on its highest temperature for 40 minutes.

Kashering: Tableware
Kashering: Utensils
How To Prepare Food in a Non-Kosher Kitchen
How to Prepare Food in a Non-Kosher Kitchen


An oven that has not been used for at least 24 hours is considered, d'oraita, to be neutral/pareve, but only if it is clean. D'rabanan, it is still not kosher, but this may be useful for when you can be lenient; e.g., if there is a safek.

Note Even when baking in a non-kosher oven, you must cook the food in a kosher utensil.


Baking in a Non-Kosher Oven

How To Tell if Oven Is Clean

To determine whether a non-kosher oven with black or brown spots is clean, scratch them:

  • If the substance crumbles, the spots are OK and you may bake non-liquid food in that oven without covering the food.
  • If the spots do not crumble or they remain immovable or come off in flakes rather than crumbles, consider the oven not clean.

Uncovered Food; Clean (Non-Kosher) Oven

You may cook food uncovered in a non-kosher oven if:
  • The oven rack and walls are clean, and
  • The food is not “liquid.”
    Note Non-liquid is defined as not being liquid before cooking OR not being liquid after cooking, but the food does not need to be non-liquid at both times.  Examples of “non-liquid” foods:
    • Apple cobbler
    • Lasagna
    • Meat (that will create gravy at the end)
    • Pudding
    • Raw fish.
Situation You plan to bake uncovered food in a clean, non-kosher oven in which the racks are not clean.
What To DoPlace two layers of foil under the baking utensil.

Double Wrapping

When To Double Wrap

Double-wrap food before baking in a non-kosher radiant-heat oven if:
  • The rack and/or oven are not clean;
  • The food that you are baking is liquid at any time during the cooking process; OR
  • Some of the food you are baking spills onto the rack or oven surfaces.

How To Double Wrap

When wrapping food for cooking in a non-kosher oven, the wrapping material does not need to seal completely, but the:

  • Food must be completely covered with two layers of foil or plastic;
  • Layers must keep water vapor out from between the layers; and
  • Surfaces of the utensil must all be covered.


Kosher Food Spilling in Non-Kosher Oven

If kosher food spills inside a non-kosher oven in which you are cooking uncovered kosher food (whether liquid or non-liquid), consult a rabbi about whether the uncovered kosher food may still be eaten.

NoteIn this case, it makes no difference whether the oven is clean or dirty because the spilled food is wet and takes on the non-kosher status of the oven. When the spilled food vaporizes, it carries the non-kosher essence to the kosher food or utensil.
NoteIf the non-kosher oven had not been used for more than 24 hours, the food is probably still kosher b'di'avad
NoteThis applies to food spilled either from the same utensil in which you were cooking the kosher food or from a different utensil.


Double Wrap Frozen Food in Non-Kosher Oven

Frozen food is considered to be wet food regarding cooking it in a non-kosher oven or regarding its being neutral for dairy and meat issues: If the oven is not kosher, the frozen food must be double wrapped, even if the oven is clean.


Heating Airline Meals in Non-Kosher Oven

Airline meals are usually non-liquid, so even if they are single-wrapped, it is OK to heat them in a non-kosher oven as long as no non-kosher food contacts the kosher food container.


Microwave Oven: Kosher Status

Introduction to Microwave Oven: Kosher Status

If a microwave oven's walls/floor/door do not become hot (more than 120° F, or 49° C), the microwave oven does not become non-kosher, dairy, meat, or non-Passover/chametz.

NoteA microwave oven that does not normally get hot, may get hotter than 120° F if you cook:

  • A liquid or moist food for a long time (even if less than 10 minutes),
  • Several liquid or moist items sequentially, or
  • Popcorn and similar foods.

If a microwave oven's walls/floor/door get hot, the oven can become dairy, meat, or non-kosher (if they become one gender and then the opposite gender is cooked or if non-kosher food has been cooked in it). If any surface--including walls, door, floor, etc.--that gets hot are plastic or coated metal, it cannot be returned to kosher or pareve. However, if the surfaces are all made of metal, they may be kasherable. Consult a rabbi.

NoteIf the microwave oven does get hot, it cannot be kashered at all--not for Passover and not from non-kosher to kosher. To check if your microwave oven gets hot, see How To Check If a Microwave Oven Will Get Hot during Cooking

Microwave Oven: Kosher Status: Walls and Door

Since microwave oven walls and doors do not normally get hot (more than 120° F, or 49° C), there is usually no need to kasher them from milk to meat (or back to milk); from ordinary use to Passover use; or from non-kosher to kosher. Just clean all surfaces.

Microwave Oven: Kosher Status: Floor

Microwave oven floors can get hot, especially where there is no rotating glass tray and the utensil is placed directly on the oven floor. All microwave ovens should be assumed to get hot unless you have tested them personally.

Microwave Floor

Cover the floor (ideally with styrofoam or another substance that blocks heat and moisture) in a non-kosher microwave oven.

Glass Tray

The glass tray does not become non-kosher and does not become dairy or meat or chametz (unless it was removed and used in a conventional oven) as long as it is clean.

Plastic Tray Support

The plastic support under the glass tray must be cleaned and must be blocked from contact with actual cooking utensils and from food if the tray:

  • Has any food of the gender opposite that of the food being cooked,
  • Has non-kosher food on it, or
  • Is dirty and you cannot tell with what.

How To Check If a Microwave Oven Will Get Hot during Cooking

To determine if the walls of a microwave oven will get hot during cooking:

  • Boil water for as long as food would typically be cooked in that microwave oven, and
  • Touch the inside walls, floor, door, and ceiling
    • If the walls are too hot to touch, the walls may acquire the gender of any food cooked in the oven. (If the walls are already the opposite gender when cooking a food, the oven may become non-kosher.)
    • If the walls are not too hot to touch, then no change of status occurs.

Non-Kosher Microwave Oven: Hot Oven, Liquid or Solid Food

If the walls of a non-kosher microwave oven get hotter than 120° F, you must double wrap any liquid or solid food you cook in that oven.

NoteIf you did not double wrap liquid or solid food cooked in a non-kosher microwave oven, consult a rabbi about whether you may eat the food.

Non-Kosher Microwave Oven: Non-Hot Oven

If the walls of a non-kosher microwave oven stay less than 120° F, you do not need to wrap or cover liquid or non-liquid food, as long as:

  1. The microwave oven is clean and dry, and
  2. If the tray is non-glass or non-Pyrex, you put a layer of separation (plastic, styrofoam, etc…) that blocks heat and any moisture underneath the cooking utensil.


Setting Down Hot Lid on Non-Kosher Stove Top

SituationYou set down a hot pot lid on a non-kosher stove top.

  • Lid is dry and stove is clean: lid remains kosher.
  • Lid is dry or wet and stove is dirty: lid is non-kosher.
  • Lid is wet and stove had hot non-kosher mixtures on it within the previous 24 hours--even if the stove is clean: lid is not kosher.
  • Lid is dry or wet and stove is clean and did not have hot non-kosher mixtures on it within the previous 24 hours: lid is kosher.


Using a Non-Kosher Kitchen Utensil
Introduction to Using a Non-Kosher Cooking Utensil

You may not use a non-kosher cooking utensil (pot, pan, baking dish, etc.) for cooking even if the utensil is clean and has not been used for more than 24 hours (unless you kasher it first).

Fruit Cut with Non-Kosher Knife
You should wash most fresh fruit cut with a non-kosher knife in order to remove whatever non-kosher food might have been on the knife from before.
Note Fruit with a sharp taste—such as lemons or tart apples—may not be used if cut with a non-kosher knife, regardless of whether the knife had been used within 24 hours.


Using a Non-Kosher Sink
A dish is still kosher b'di'avad if heated to 120° F (49° C) or more in a clean, non-kosher sink that had remained below 120° F for the previous 24 hours.

Toveling (see Tahara/Tum'a)