Cooking on Shabbat

In Jewish law, the seventh day of the week (Saturday) is "Shabbat", a day of rest. There are 39 categories of biblically prohibited activities which may not be performed on "Shabbat", and this article will focus on the eleventh prohibited activity, that of cooking on "Shabbat".

"Bishul" versus cooking

The eleventh prohibited activity is called "bishul" (בישול) and is best translated as "cooking." However, the prohibited activity of "bishul" is not equivalent with the English "cooking" because many actions that the average person would refer to as cooking are in fact not forbidden by the prohibition of "bishul" and many actions that the average person would not refer to as cooking do in fact fall under the prohibition of "bishul", as evidenced by the examples below. For this reason, it is best to maintain the English transliteration of "bishul" rather than try to discuss the prohibited activity with a thoughful yet wholly inadequate translation.

Definition of "bishul"

The definition of the Hebrew term "bishul" as it relates to "Shabbat" is the "use of heat to alter the quality of an item," ["Igrot Moshe" "Orach Chaim" 2:85] and this applies whether the heat is applied through baking, boiling, frying, roasting and most other types of cooking. ["Bavli" "Shabbat" 40a] ["Talmud Yerushalmi" "Shabbat" 87:2] While the prohibition includes using heat to alter the quality of even non-food items, such as metal or wax, this article will focus on "bishul" as it relates to food items.

Foods subject to the prohibition

The prohibition of "bishul" applies to all types of food and drink, even to those foods and drinks which are edible when raw or cold. [Although Maimonidies classifies the cooking foods that are edible when raw as rabbinically prohibited, the "Birchei Yosef" is in doubt whether this is biblically or rabbinically prohibited ]

Heat sources as they relate to "bishul"

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quote = "Kli Rishon"A "kli rishon" (כלי ראשון, "first vessel") is a vessel that was heated directly on a flame or other source of heat. Even when removed from the source of heat, this vessel maintains its status as a "kli rishon", and possesses the capacity to enact "bishul" on any type of food placed within it. This capacity remains until the pot and its contents cool below the temperature of "yad soledet bo" (יד סולדת בו, the degree of heat "from which the hand recoils").
source = Rabbi Simcha Bunin Cohen, "The Shabbos Kitchen" Mesorah Publications, Ltd. 1991, page 17
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align = rightThe prohibited activity of "bishul" is separate and distinct from that of "havarah" (הבערה, "kindling a fire") and performing "bishul" with a pre-existing flame is forbidden on "Shabbat". The prohibition of "bishul", however, is not limited to the use of fire as a heat source; it is forbidden to perform "bishul" with any source of heat, whether it be an actual flame, or an electric range, a hot plate, an urn ["Beit Yitzchak" "Yoreh De'ah" 120] ["Maharam" 2:246] or a microwave oven. ["Igrot Moshe" "Orach Chaim" 3:52] Moreover, placing food into a "kli rishon" may constitute "bishul" in certain instances, as will be explained in greater detail below.

Reheating foods

While it is prohibited in most instances to initially heat a food item to the temperature of "yad soledet bo", foods that have already been fully cooked may sometimes be reheated. In terms of reheating, a distinction is made between dry foods and liquids.

Dry food that has been completely cooked is no longer suject to the prohibition of "bishul"; this is based on the principle of "ain bishul achar bishul" (אין בישול אחר בישול, "Cooking does not take effect after cooking"). Thus, a completely cooked, dry food item, such as a piece of chicken or potato kugel, may be reheated once it has been fully cooked.

However, there is a great dispute as to whether this rule applies to liquids: whereas "Rashi", ["Bavli" "Shabbat" 18] the "Rosh" ["Shabbat" chapter 3] and "Rabbeinu Yonah" [as quoted by the "Ran" in "Shabbat" chapter 4] agree that this rule does not apply and reheating of liquids is forbidden, Maimonidies, ["Hilchot Shabbat" 3:3] the "Rashba" and the "Ran" assert that liquids are in fact no different than solid dry foods. In practice, we are stringent and apply the principle of "yeish bishul achar bishul" (יש בישול אחר בישול, "Cooking does take effect after cooking"). This prohibition of reheating liquids, however, only applies when the liquid has completely cooled. If the liquid has only partially cooled and still retains enough heat to be enjoyed as the warm liquid as it was intended to be, ["Shulchan Aruch HaRav" 69] it may be reheated.

Although, in a particular instance, there may be no biblical prohibition in regards to recooking a food item, rabbinical regulations are in place dictating exactly how food may be reheated.

Using a different form of cooking for reheating

As mentioned above, the prohibition of "bishul" applies equally to all forms of conventional cooking, whether foods are boiled, baked, fried or roasted. These are, howeve, distinct methods of cooking, and although any food item prepared in one manner may be reprepared in the same manner according to the guidlines above, one may not, for instance, bake an already boiled food item, as this will constitute a form of "bishul". ["Shulchan Aruch" 318:5 + associated "Mishnah Brurah"]

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