Question: Is one allowed to use an electric slow cooker (such as a Crock-Pot) that fits into another pot for the purpose of maintaining hot food on Shabbos?
M. Goldblum
Answer: Rishonim and poskim debate whether one may partially cover the sides of a hot pot before Shabbat, leaving only part of it exposed. Is such partial covering considered hatmana (storing or wrapping food in a manner that adds heat)?
The Rashba (Novella 48:1), among others, argues that it is, and the Mechaber (Orach Chayim 253:1) rules accordingly. Rabbeinu Tam and others, however, rule that it isn’t, and the Rema (Orach Chayim ad. loc.) rules accordingly.
As a general rule, Sephardim follow the rulings of the Mechaber and Ashkenazim follow the rulings of the Rema. As such, it seems that Sephardim may not – but Ashkenazim may – use a pot that sits within, and whose sides are covered, by another pot.
But is this the kind of partial hatmana permitted by the Rema? Perhaps too much is covered for it to be considered a “partial” covering. The Pri Megadim poses this question, and there are conflicting implications in the writings of poskim who allow partial hatmana (see Pri Megadim 259:3, citing Taz 253:14; see also Mishnah Berurah 257:41 and 253:48, 69).
Rabbeinu Tam writes in Sefer HaYashar that hatmana is prohibited if most of the pot is covered. The Chayei Adam (2:5), on the other hand, rules that hatmana is only prohibited if the substance used for wrapping touches the pot on top, on bottom, and on all sides. Thus, there is no hatmana problem if even a little bit is uncovered. And there is no hatmana problem if one places food in an oven since the oven doesn’t touch the pot on its top or sides.
Some distinguish between wrapping food on erev Shabbat with containers that are a source of heat and wrapping food with containers that are not a source of heat. In their view, if food is wrapped in a blanket and placed over a blech (assuming there’s no fire hazard), there is reason to be lenient since the blanket is not a source of heat.
But the outer pot of a slow cooker is a source of heat and therefore perhaps shouldn’t be used. Indeed, this seems to be the general position of the Chayei Adam (20:22) – although he would insist that the prohibition only applies if the outer pot touches the inner one on all sides.
Rabbi Moshe Feinstein (Iggrot Moshe, Orach Chayim Vol 4, 74:3) was asked about wrapping a solid food in aluminum foil and placing it on a pot on a blech on Shabbat. Rav Moshe said doing so is prohibited because the wrapping is mosif hevel (adds heat). Both elements are required for the prohibition to kick in; there needs to be a wrapping and it needs to add heat.
(to be continued)