Hatmana - Restriction

QUESTION: I am aware that hatmana (insulating food to preserve the heat) is forbidden before and during Shabbos. Under what circumstances does this restriction apply?

ANSWER: There are separate rules for hatmana before and during Shabbos. In this Halacha Yomis we will discuss insulating hot food on Shabbos. 

On Shabbos, one may not wrap up hot food to preserve its heat. Chazal were concerned that if one insulated hot food on Shabbos and then discovered that the food is not as hot as desired, the person may reheat the food on Shabbos. Even dry, fully cooked foods about which we say “ain bishul achar bishul” (the prohibition of bishul does not apply) may not be insulated on Shabbos. Chazal forbade insulating on Shabbos because they were concerned that one might stoke the coals to speed up the process and violate the melacha of making a fire on Shabbos. However, if one insulated food on Shabbos, even if it was done intentionally, the food is permitted. The Mishnah Berurah (257:8) explains that since the food was already hot, keeping the food hot longer is not considered a significant benefit that would make the food prohibited. 


The Gerald & Karin Feldhamer OU Kosher Halacha Yomis is dedicated to the memory of Rav Yisroel Belsky, zt"l, who served as halachic consultant for OU Kosher for more than 28 years; many of the responses in Halacha Yomis are based on the rulings of Rabbi Belsky. Subscribe to the Halacha Yomis daily email here.