Note: this is the first installment of a 3-part series on kashrut. For Part II, click here; for Part III, click here.
Dear Josep,
One of the very first topics we discussed to do with Judaism was kashrut. A little reminder, pulled from the post about how we met:
At lunch that day, while I picked at my sliced cucumbers, he asked me, “What if we went to my house and I bought kosher ingredients and cooked for you?”
I looked over at this person who had literally just offered to bring home a random girl from another country, whom he had known for a grand total of 72 hours, and cook her a meal. I shook my head. “No… all the pots and pans would have to be kosher…”
“What if I bought a new pan?”
He couldn’t be serious.
“That’s very nice of you to offer… but it’s not just the pans… it’s all the utensils and the oven and everything…”
“Is there a way to make them kosher?” he insisted.
I smiled ironically. “Uh… yeah…. but trust me, that’s not going to happen.”
“Why not? What would I need to do?”
“Just trust me. You don’t wanna know.”
“Tell me. I want to know.”
I eyed him skeptically, eyebrows raised. “You really want to know?”
“Yes.”
I shrugged. “Okay… you asked.” Thereupon I launched into a long, rambling explanation of how one kashers a kitchen, which for the uninformed among you, is a long, painstaking, arduous process that involves a lot of scrubbing, boiling water, and otherwise heat-treating everything. The goal of this tirade was to illustrate just how crazy an idea this was, and I assumed that after a few sentences his eyes would glaze over in boredom and that would be that. As predicted, everyone else who had been listening quickly lost interest and began chatting among themselves as I rambled on. But when I glanced at him somewhere in the middle of expounding upon mugs and soapy water in the microwave, he was still watching me as though I was giving him a thrilling play-by-play of the latest Barcelona vs. Madrid soccer game. I skidded to a stop and exclaimed, “Why are you even still listening to me?”
For reasons I can still not fathom, you are still listening to me, and I think it is high time I gave you a proper explanation of this whole crazy business called kashrut. Or, in the immortal words of the guy at the supermarket in Barcelona upon being asked where the kosher section was: “Jew food.”
This is such a broad topic we are not going to cover it in one entry. We’re going to start with a general overview and then get into detail about animal products. In Part II, we’ll talk about the various issues involving fruits, veggies, and grains, and in Part III we will talk about the nitty-gritty details, like how to make vessels or dishes that were kosher, non-kosher, and vice versa, as a somewhat more organized recap of that rambling speech I gave you eight years ago. 😉
So:
What Is Kashrut?
Kashrut is the observance of the dietary laws of Judaism. The adjective is “kosher”, and these words come from the Hebrew root כ.ש.ר, k.sh.r., meaning “proper”, “fit”, “appropriate”. “Non-kosher” is also known in Yiddish as treif, from the word treifa in Hebrew, which means “carrion”.
The rules of kashrut are derived from the Torah, and it is one of the very basic commandments that–along with Shabbat observance–draws the line between observant Jews and non-observant Jews.
There is no reason given in the Torah for why these laws must be observed. Many sages have tried to explain it in various ways, but ultimately, this is what we call a chok–the type of commandment that has no known reason. In other words, a “Because I Said So” commandment. 😉 We observe it out of loyalty to God and the belief that there is Divine reason behind it, even if we humans don’t or can’t comprehend it.
For a practice with no obvious explanation, it is fairly remarkable how strongly kashrut has held within the Jewish community. Many people who don’t consider themselves religious make some effort towards kashrut, such as avoiding pork and shellfish. As you know, many of the practices that survived in families of crypto-Jews were practices to do with kashrut–checking eggs for blood, separating milk and meat, separating the fat from the meat, etc. This is testimony to the deep importance and significance of this mitzvah.
At its very basic, kashrut involves:
1) Only eating meat, milk, or eggs produced by animals that are designated as kosher, and then, only if they are slaughtered in a certain way;
2) Not eating forbidden parts of animals (namely: blood, certain parts of fat, the sciatic nerve, and a severed limb from a live animal);
3) Complete separation of dairy products and meat products;
4) Eating only produce that has been grown and harvested in accordance with the agricultural laws (if the land is in Israel and owned by a Jew. Otherwise those laws don’t apply), the laws regarding tithing (separating portions to give to the poor, and in the days of the Temple, to the Cohanim and the Levites) and properly checked for insects (as per item #1);
5) Other “fences” put in place by the rabbis to prevent various issues or commemorate practices which are no longer practiced without the Temple, which we will get into as they come up.
This may sound simple enough, but if you are really committed to keeping these laws to the letter, some difficult questions are going to come up. For example: how do we eat meat but not the blood, especially in an organ such as the liver, which is completely saturated with blood? Is it okay to eat a piece of kosher meat that was cooked together with a piece of non-kosher meat? How many measures must we take to make sure our food is bug-free before resigning ourselves to the fact that we aren’t going to catch everything? What counts as “meat” anyway in terms of separating from dairy? Does poultry count? What about fish?
And this, my friend, is why a huge chunk of rabbinic literature is devoted to answering these questions and setting down the principles on which to answer further questions. And this is also why we need rabbis. Rabbis are basically experts in Jewish law. Because you can’t expect your average Joe (-seph?) to know all the details of these laws, you have these experts in every community who have studied the laws thoroughly and can answer questions that arise on a day to day basis. That is the main function of the observant rabbi.
So, let’s get to it:
Which Animals Are Kosher?
Mammals
Most people know that Jews can’t eat pork. Pigs are one of the animals listed explicitly in the Torah as not being kosher. But the pig is actually the last in a list of four animals that are mentioned explicitly: the camel, the rock-badger (also called the hyrax), and the hare. All other mammals are ruled out by exemption.
Kosher mammals must meet these two criteria: 1) They must have split hooves:

Photo credit: DRosenbach, under CC BY-SA 3.0
2) They must chew their cud.
Chew their what?
…Right. So, there are certain herbivores that have a curious way of digesting food. Plants are pretty hard to digest because of all the fiber. So these animals have multiple stomachs, and the food gets swallowed, brought up again, and chewed multiple times before it is fully digested. This multi-chewing process is called “chewing one’s cud”.
Practically speaking, this means that cows, sheep, goats, and deer are kosher. (So are… giraffes. There’s an urban myth that the reason we can’t eat them is that their necks are so long we don’t know where to cut it to slaughter them in the kosher manner, but that isn’t true. We don’t eat them for the same reasons everyone else doesn’t…) Pigs are specifically mentioned as non-kosher because while they do have split hooves, they don’t chew their cud. Camels, hares, and rock-badgers chew their cud, but their hooves are not split.
Birds
In principle, kosher fowl do not have “criteria”. There is a list in the Torah (Leviticus 13-20) of birds that are not kosher, and all others are assumed to be kosher. The problem is that over time, the names referring to specific birds have been forgotten, so we aren’t sure what some of them are. The sages came up with a number of criteria that the kosher birds seem to have in common, such as the structure of the foot and the presence of a crop (a little pocket of skin for storing food before it enters the stomach), etc. One obvious thing that kosher birds have in common, is that none of them are birds of prey.

Kosher birds commonly eaten are: chicken, turkey, goose, and duck. Quail, pigeons, doves, and swans are also kosher.
Seafood
Kosher seafood is once again identified by two criteria: it must have fins and scales. So commonly eaten fish like salmon, tuna, carp, mackerel, sardines, perch, etc., are fine. Exotic fish like swordfish and sharks are not (they don’t have scales), and neither are shellfish of any kind (no shrimp, lobster, or crab).

Photo credit: Elapied
Speaking of which…
Creepy Crawlies
In our Western world this makes us all go “uugghh”, and indeed, most bugs, worms, etc. are not kosher. Frogs, snakes, and lizards are also included in this category (“shratzim“=creatures that creep on the earth). But, there are certain kinds of locusts that are kosher. I am told they are a delicacy in some parts of the world. I am not sold. :-/
Kosher Slaughter: Shechita
Very simply, kosher animals must be slaughtered by slitting their throats quickly, with a very sharp knife, in a way that strikes major blood vessels leading to the brain, leading to immediate and irreversible loss of consciousness. This must be done very precisely so as to cause minimal suffering to the animal, and therefore shechita is a craft that must be studied carefully for one to be able to slaughter an animal in a way that renders it kosher. The purpose, obviously, is to slaughter to animal in a way that is as humane as possible. A certified Jewish ritual slaughterer is called a shochet.
What is the difference between shechita and dhabiha (slaughter in accordance with the laws of halal)? For meat to be halal, the name of God must be invoked before the slaughter. It so happens that there is a blessing Jews recite over the mitzvah of shechita, meaning that the name of God is usually invoked, and that is why many Muslims feel comfortable eating kosher meat. There is a whole Wikipedia article comparing and contrasting kashrut and halal.
Preparing Kosher Meat
So once the animal is dead, the blood of the animal must be covered with earth, and then the blood must be removed from the meat. This is done through a process of salting, which is where “kosher salt” got its name. A more accurate name would be “kashering salt”, as its purpose is to kasher (=make kosher) the meat. All salt is kosher.
I am told that kosher meat is thus drier and saltier than non-kosher meat.
As to our question about livers before, salting is not enough to remove the blood from liver, and therefore liver must be broiled in a way that draws out the blood. Other meat can be kashered this way too.
Milk and Meat
One very common question among newcomers to Judaism–or skeptics–is, how on earth did we get from “don’t cook a kid in its mother’s milk” (Exodus 23:19 and 34:26, and Deuteronomy 14:21), to waiting several hours after consuming any kind of meat, until consuming any kind of dairy?! This is one of the prime examples of the importance of the Oral Torah, the oral tradition passed down from generation to generation through the sages and rabbis, that we believe has its source at Mount Sinai along with the Written Torah. Through the oral tradition we know that this phrase refers to all cattle meat and all milk. There are a number of different explanations given for why the Written Torah specifies “kid in its mother’s milk”, but this is one of the things in the oral tradition that the rabbis are in completely unanimous agreement about, which as you know, isn’t to be taken lightly! 😉
The sages did expand cattle meat to include all other kinds of meat and poultry–but not fish or locusts.
Why do we wait between eating meat and milk? That also has a number of explanations, but it also comes to demonstrate the severity of this practice and how very careful we are to maintain this complete separation. There are different traditions about how long to wait, ranging from one hour to six hours. We wait three.
That’s quite enough for now! Stay tuned for Part II. 🙂
Love,
Daniella
Don’t miss the other two posts in the Jew Food series:
I only heard the term “kosher salt” very recently. It must be an American thing. In England we call it coarse salt.
Excellent intro!
1. It must be said about the locusts that only in cultures with a tradition of eating them-that know exactly what type of locusts-can eat them.At least from what I know…
2. The Halal issue is interseting…
I think it’s not only an issue of knowing the right type–there are simanim–but also of it being considered a “davar meguneh” (“repulsive thing”) in other cultures, which you are not allowed to eat even if it is technically kosher.
Minor quibble, but covering the blood of a slaughtered animal is only for birds and game animals. This excludes cows and sheep, for instance.
Not so much a quibble as a clarification 🙂 Thanks!