In the religious and dietary laws of the Jewish people, the term "kasher" is applied to the preparation of meat and poultry, and means "to render fit" or "proper" for eating.
1. To render meat "fit" for food, the animal must be killed and cut up according to the Jewish method of slaughter, and must be purchased from a Jewish butcher.
2. The meat should be put into a pan, especially reserved for this purpose, entirely covered with cold water, and left to soak for half an hour. Before removing the meat from the water every particle of blood must be washed off. It should then be put upon the salting board (a smooth wooden board), placed in a slanting position, or upon a board with numerous perforations, in order to allow the blood to freely flow down. The meat should then be profusely sprinkled on all sides with salt, and allowed to remain in salt for one hour. It is then removed, held over a sink or pan, and well rinsed with cold water three times, so that all the salt is washed off. Meat left for three days or more unsoaked and unsalted, may be used only for broiling over coals; it may not be cooked in any other way.
The ends of the hoofs and the claws of poultry must be cut off before the feet are kashered.
Bones with no meat or fat adhering to them must be soaked separately, and during the salting should not be placed near the meat.
3. The liver must be prepared apart from the meat. It must be cut open in both directions, washed in cold water, and broiled over the fire, and salted while it is broiling. It should be seared on all sides. Water must then be poured over it, to wash the blood away. It may then be used in any manner, as the heat has drawn out the blood. Small steaks and chops may be kashered in the same way.
4. The heart must be cut open, lengthwise, and the tip removed before being soaked, so that the blood may flow out. The lungs likewise must be cut open before being soaked. Milt must have veins removed.
5. The head and feet may be kashered with the hair or skin adhering to them. The head should, however, be cut open, the brain taken out, and kashered separately.
6. To kasher suet or fat for clarifying, remove skin, and proceed as with meat.
7. Joints from hind-quarters must not be used, until they have been "porged," which means that all veins of blood, forbidden fat, and prohibited sinew have been removed. In New York City no hind-quarter meat is used by orthodox Jews.
8. All poultry must be drawn, and the inside removed before putting in water.
Cut the head off and cut the skin along the neck; find the vein which lies between the tendons, and trace it as far back as possible; at the back of the neck it divides into two branches, and these must be removed.
Cut off the tips of the wings and the claws of the feet. Proceed as with meat, first cutting open the heart and the liver. Eggs found inside of poultry, with or without shells, must be soaked and when salted be placed in such a position that the blood from the meat does not flow upon them. Such eggs may not be eaten with milk foods.
In conducting a kosher kitchen care must be taken not to mix meat and milk, or meat and butter at the same meal.
The utensils used in the cooking and serving of meat dishes may not be used for milk dishes. They should never be mixed.
Only soaps and scouring powders which contain no animal fat are permitted to be used in washing utensils. Kosher soap, made according to directions for making hard soap, may be used in washing meat dishes and utensils.
To follow the spirit as well as the letter of the dietary laws, scrupulous cleanliness should always be observed in the storing, handling and serving of food.
It is very necessary to keep the hands clean, the flours and cereals clean, the ice-box clean, and the pots and pans clean.