We are continuing in siman 5, discussing the halachos of hatmana. We left off with a contradiction in the Chayei Adam. On the one hand, he writes that hatmana b’miktzas is muttar, but on the other hand, he only allows for the coffee pot to be submerged in sand if the majority of the pot is uncovered, following the opinion of the Shulchan Aruch that hatmana b’miktzas is assur.
We also learned that the Mishnah Berurah follows the opinion of the Chayei Adam that it is assur unless it is less than half insulated, and also follows the Rema who holds it is muttar evem if completely insulated.
In sefer Orchos Shabbos vol. 1, the authors discuss this contradiction in biurim 2. They suggest that there is a difference between the scenarios, in that one is a maamid hevel and one is a mosif hevel. When it comes to hatmana b’miktzas with a maamid hevel, the Mishnah Berurah paskens it is muttar. When the Mishnah Berurah says hatmana b’miktzas is assur, it is referring to using an insulator which is mosif hevel, and it is in such a case that the Mishnah Berurah paskens the pot must be half or more uncovered.
It is difficult to work out their suggestion in all of the scenarios of the Mishnah Berurah. There is one scenario in which the Mishnah Berurah discusses performing hatmana in hot water, which is mosif hevel, where the Mishnah Berurah says it is muttar as long as the food is not fully enclosed. According to this understanding, since the hot water is mosif hevel, it should only be muttar to perform hatmana if it is less than half submerged.
The Orchos Shabbos continues, and writes that if we understand that when it comes to mosif hevel, hatmana b’miktzas is assur (unless it is less than half insulated), a crockpot should be assur. Although the top may be open, it is more than one half insulated, and since the crockpot is mosif hevel, it should be completely assur to use on Shabbos.
However, we need to clarify whether a crockpot is hatmana to begin with or not. There is a thin gap of airspace between the walls of the inner pot and the crockpot wall. In theory, this airspace should mean that the inner pot is not considered insulated, so there should be no issue of hatmana. The Orchos Shabbos argues that even though there is a thin gap, since this is the way it is used to cook, it is still considered hatmana. He writes that he presented his suggestion to his uncle, Rav Shlomo Zalman Auerbach, ztl, who agreed with him. He also brings a teshuva from Rav Wosner, who disagreed and held it is not considered hatmana. The sefer Piskei Teshuvos brings Rav Moshe Shternbuch, among others, who also disagree and do not consider a crockpot to be hatmana.
Even if there is no gap between the pot and walls, we also have the consideration that it is only hatmana b’miktzas, which, although part of a contradiction, are muttar according to both the Mishnah Berurah and Chayei Adam in one place.
Some are machmir on this issue, and therefore put something (often tinfoil) under the pot, between the pot and the floor of the crockpot. Rav Elyashiv explains that it gains that both the bottom and the part of the inner pot raised outside of the crockpot are not insulated by the crockpot, meaning that even according to the opinion that one should be machmir, the pot is less than half insulated. If so, even according to this machmir understanding that a crockpot is mosif hevel, this hatmana is muttar.
Practically, many poskim are meikil and hold it is not considered hatmana at all, since it is not touching. One should consult their rav.
Summary
There is a contradiction in the Chayei Adam and Mishnah Berurah regarding whether hatmana b’miktzas is muttar, or whether it needs to be less than half insulated. One possible ramification of this contradiction is crockpots, and the need to place something between the bottom of the crockery and the crockpot so that the crockery is less than half insulated. Nevertheless, many poskim are meikil, so one should ask their rav.
