- Question: [Thursday, 30th MarCheshvan 5783]
The kitchen department of our learning institution which contains a dormitory just purchased a warming cabinet which is meant to store food after it is already cooked so it stays warm. I would like to know if there’s any issue with us using this on Shabbos, both for leaving the food inside of it into Shabbos, and likewise to return food into it on Shabbos to heat it up? We spoke to another learning institution who also has a similar warming cabinet, and they told us that they use it on Shabbos to heat up food and they are not aware of any issue with doing so and their rabbi said it was okay. So I would just like to confirm.
Leaving into Shabbos: There is no issue with leaving fully cooked food, or even half cooked food, in the warming cabinet into Shabbos.
Opening and closing on Shabbos: Regarding opening the oven door to remove food from it on Shabbos, this follows the same laws a regular oven: If opening and closing the door does not have any electronic effect on the appliance, such as if it does not turn on and off based on the temperature inside, and always remains on by a set temperature, then there is no issue in opening and closing the door. If, however, it is temperature based in opening the oven door causes the temperature to go down which may cause the heating element to turn on, then one should only open the door when the heating element is already on. For this reason, it is best to get a warming cabinet that contains a Shabbos mode.
Returning and heating food in it on Shabbos if the temperature is Yad Soledes: If the warming cabinet does not have one set temperature, and rather contains the feature to change the temperature to higher and lower, then it is forbidden to return any foods to this oven on Shabbos, and certainly one may not initially heat foods in this warming cabinet on Shabbos, just as is the law regarding a regular oven which is not Gerufa Uketuma [i.e. covered inside with tinfoil]. If the warming cabinet has only one set temperature which cannot be changed, then it is permitted to return food to it on Shabbos, if all six Chazara conditions are fulfilled just as is required when returning food to a Blech or electric plate. Thus, one cannot initially warm food in the warming cabinet on Shabbos. Nonetheless, seemingly those who are lenient to warm food directly on a Shabbos Plata [if there is no cooking prohibition with the food, such as fully dry and fully cooked], then they may likewise be lenient here to initially heat foods in it on Shabbos that do not contain a cooking prohibition.
Returning and heating food in it on Shabbos if the temperature is Yad Soledes: Many warming cabinets have a temperature range between 95-150 Fahrenheit which one can choose to set for the cabinet. Meaning, that it is possible to set your warming cabinet to be a temperature that is less than Yad Soledes [i.e. 110 F.]. If this is the case, then the following law applies: All foods may be left inside it into Shabbos, although on Shabbos itself foods may not be returned to it on Shabbos, and certainly may not be initially placed into it on Shabbos, unless the warming cabinet does not contain adjustable temperatures and is always a set temperature that is below Yad Soledes, in which case one may seemingly even initially place food in it on Shabbos to get warm.
Explanation: Leaving food and returning food and heating food in a warming cabinet on Shabbos follow similar laws to that of a regular oven with two differences: 1) the appliance is not used for cooking and hence is more lenient than a regular oven regarding the worry of Michzi Kemivashel, and hence the Poskim conclude that even according to the main opinion which prohibits returning any food inside of an oven on Shabbos, they would be lenient in this case. 2) Some warming cabinets have the option of setting the temperature for below Yad Soledes, which cannot cook, and hence touches on the subject of heating foods on Shabbos inside of an oven which is not Yad Soledes. Practically, if the warming cabinet is set to a temperature that is above Yad Soledes, and it is possible to change in temperature, then it is never permitted to return food to it on Shabbos due to the decree that one may come to change the temperature, and it is similar to returning or heating food on an open flame on Shabbos which is forbidden to be done. Furthermore, even if the temperature of the warming cabinet has been set to less than Yad Soledes, since it is possible to change the temperature, seemingly it would still be forbidden to return and initially place food in it on Shabbos due to worry that one may come to raise the temperature, as the Halachic allowance given in the Poskim regarding less than Yad Soledes ovens all refer to heating sources which have had Gerufa Uketuma performed to them, and are hence synonymous to ovens whose heating elements have been turned off. This is very different than a warming cabinet in which the heating element is still on and no Gerufa Uketuma has ever been performed to it. If, however, the warming cabinet has a set temperature that cannot be changed, then it would follow the same law as a regular electric plate, in which if the set temperature is above Yad Soledes then many are stringent to not heat things on it on Shabbos without fulfilling all six Chazarah conditions, and some are lenient to even directly heat on it foods that do not contain a cooking prohibition. And if the set temperature is below Yad Soledes, then it would seemingly be permitted to even initially warm food in it on Shabbos, just as we rule by a less than Yad Soeldes electric plate.
Sources: See regarding leaving food in an oven into Shabbos that if the food is half cooked it is valid to be done: Admur 253:8-9; See regarding the restriction of Michzi Kimivashel in initially heating foods on Shabbos: Admur 253:14, 15, 18, and 24; Shabbos Kehalacha Vol. 1 page 341; See regarding returning foods into an oven on Shabbos: Admur 253:16, 19; Michaber and Rama 253:2; Modern day ovens: Aruch Hashulchan 253:17; Sheivet Haleivi 3:48 and Igros Moshe 4:74-26; Minchas Yitzchak 3:28; Shemiras Shabbos Kehilchasa 1:17; Shabbos Kehalacha Vol. 1 page 383; Piskeiy Teshuvos 253:8 See regarding returning foods to warming cabinets on Shabbos that have one set temperature: Koveitz Paamei Yaakov Kuntrus 37 p. 134-135; Shabbos Kehalacha 9:38; [Vol. 1 page 387]; Piskeiy Teshuvos 253:8 footnote 78; See regarding heating foods by a less than Yad Soledes heat source on Shabbos: Admur 253:5, 19, 21; M”B 253:93 in name of Gr”a; Shaar Hatziyon 253:93; Igros Moshe 4:74; Shabbos Kehalacha ibid; Kitzur Diney Shehiyah and Hatmanah 259; See regarding initially leaving foods on a Blech on Shabbos: Admur 253:26; Mahram Brisk 2:76; Maharam Shick 117; Shabbos Kehalacha Vol. 1 page 411-414; Piskeiy Teshuvos 253:28-29 and footnote 264; SSH”K 1; Igros Moshe 1:93; 4:74-32; See regarding initially leaving foods on an electric plate on Shabbos: Shabbos Kehalacha Vol. 1 pages 416-418; Piskeiy Teshuvos 253:28