Ridiculously Quick Guide to Keeping Kosher

Note: Different denominations and sects of Judaism adhere to widely different rules. Even within a denomination or sect (and especially within the Conservative Movement), Jews may keep kosher in very different ways.

What foods are kosher?

The basic list is:
  • Vegetarian food.
  • Kosher beef and lamb. That is, it must be schechted, or killed through kosher slaughter. This is a complicated process, but the upshot is kosher meat must be marked "KOSHER" on the package.
  • Kosher chicken, turkey, duck, quail and some other less common poultry.
  • Scaly fish.

What foods are not kosher?

Plenty, which is why it's worth writing an article about it:
  • All pork products, including bacon and ham. Or any other mammal that does not have cleft hooves and chew its cud.
  • All shellfish, including shrimp, lobster and crab.
  • In fact, no invertebrates, reptiles or amphibians are kosher, with the exception of four specific species of locust found on the Arabian peninsula.
  • Fish that do not have scales, or which feed on the bottom of the ocean. Thus, you won't find catfish on the Rosh Hashannah table. (You'll find beef brisket and turkey, usually.)
  • Any kosher land animal that was not schechted.
  • Any foods which combine dairy and meat, even kosher meat. Jews who keep kosher can eat cheese and beef can be kosher, but there's no such thing as a kosher cheeseburger.
  • Orthodox Jews, many Conservative Jews and many post-denominational Jews with traditional leanings will not eat any (or sometimes only any hot) food prepared outside of a kosher kitchen. A kosher kitchen is one which has separate dishes, pans and utensils for meat and dairy foods and which has not been contaminated with non-kosher foods. Other Conservative Jews and virtually all Reform Jews may keep a kosher kitchen at home but will be more flexible when eating in restaurants or others' homes.
  • Orthodox Jews will not drink wine that was touched by a non-Jew while it was being made or after it was opened.
  • In general, Orthodox Jews need any food besides fresh produce to be marked as kosher.
That's pretty much it! Also keep in mind: "Anything that's 99% kosher is 100% non-kosher." This is why most Jews who keep kosher will not eat Starburst or most gummy candies (they contain gelatin).

Why do Jews keep kosher?

Put three Jews in a room and you get ten opinions. So there's no conventional response to that question. Here are some common responses you might hear, though:
  • My parents raised me to keep kosher.
  • God commanded us to keep kosher.
  • The Torah says to keep kosher.
  • The Rabbis said to keep kosher.
  • My rabbi encouraged me to keep kosher.
  • I live in Israel and it's virtually impossible not to keep kosher.
  • Keeping kosher binds me to my community.
  • Keeping kosher ties me to a tradition and culture that dates back 3,500 years.
  • It feels good to exercise self-discipline.
  • I'm vegetarian so I kind of keep kosher by default.
  • I've always kept kosher.
  • Non-kosher foods gross me out.
  • I would feel really guilty if I didn't keep kosher.
  • What would my (parents/teachers/friends/rabbis/girlfriend/boyfriend/wife/husband) say if they knew I didn't keep kosher?

Who came up with these laws?

Depends on the law. Most of them come directly from the Torah, a very old document that Christians call the Old Testament. I know the rule that chicken must be schechted and that wine can't be touched by non-Jews were devised by religious scholars sometime between the writing of the Torah and the writing of the Talmud, 1,500 years later.

The rules are still changing to this day. The Rabbinical Assembly of the Conservative Movement, for example, has loosened restrictions on wine and passed down an ambivalent opinion on highly-processed gelatin.

How do I make sure that my kosher friend can eat my cooking?

Your best bet is to ask. Because the way Jews keep kosher vary from person to person, it's hard to know what your friend will or will not eat. The strictest/safest way would be to only serve undressed raw vegetables on a glass plate, but that may be too limiting and unnecessary.