Warming Food on Shabbos part 1
Cooking is one of the thirty nine categories of creative activities prohibited on Shabbos. All of the various forms of cooking such as baking, boiling, frying, and roasting are prohibited.
Food should be totally cooked before the onset of Shabbos. One should try to complete all cooking by the time Shabbos candles are lit. This is especially important during the winter when Shabbos begins very early.
Even though cooking is prohibited one may keep cooked food warm on Shabbos. One who wants to keep food warm on the stove top during Shabbos needs to cover the flame or heating element. It is most practical to use a sheet of metal called a blech. Many authorities maintain that it is proper to cover or remove the knobs of the stove so that it is impossible to change the temperature of the burner. If one is using a crockpot or a hot plate he is encouraged to ask a competent halachic authority for guidelines regarding its proper usage.
Cooked solid foods are not subject to the halachic process of “cooking” if they are reheated in the same manner they were originally cooked. However, one may not place a cold solid food directly on the blech on Shabbos to heat it up. One may place it on top of a pot already on the blech. According to many authorities he may take an empty dry pot and place it on the blech upside down and place the food on top of the pot. He should make sure there is no liquid together with the food that might get cooked.
Stirring is one of the procedures which expediates the cooking process. One may not stir a pot of food while it is on a heat source. He may remove the pot and then stir it. In order to return the pot to the blech he needs to keep the following things in mind: 1) that he intends to return the pot; 2) he should not let the pot out of his hands; 3) the food should still be warm. If he forgot step 1 or 2 he may still return the pot to the blech.
