Permissible ways to heat up food on Shabbat: Difference between revisions

* The Mishnah (Shabbat 36b) records Beit Hillel’s opinion that one may not return a pot to a Kirah (type of stove meant to hold two pots) on Shabbat if the Kirah is heated with pressed sesame or wood unless the coals were covered with ashes or removed.  

* Rashi Shabbat 36b "lo machzirim" says its "mechzay kimivashel", meaning, that the reason Chazal prohibited placing fully cooked food on the fire on Shabbat is that it looks like one is cooking on Shabbat. Baal HaMoar 16b, Rashba (38b D”H MeKlal) in name of some geonim, Ritva (40b D”H VeAskina), and Ran (17b D”H Bei Rav Ashi) write that the prohibition of Hachzara is a gezerah of Chazal because it looks like cooking when one heats up cold food on [[Shabbat]]. Mishna Brurah 253:55 quotes this Ran.

* The Gemara and Rishonim discuss under what conditions may one return food to the fire. Based on the Rama 253:2, Shemirat Shabbat KeHilchata 1:18 rules that one may return food to a fire on Shabbat only under the following conditions: 1) the food is fully cooked, 2) it’s still somewhat hot (see the footnotes to [[#The opinion of the Ran]] about which foods need to be somewhat hot), 3) it was removed with intent be to returned, 4) one kept his hand on it, and 5) the fire is covered. For the slightly variant conditions according to Sephardim, see Yalkut Yosef 253:9.</ref>

# One may not return food to the oven on [[Shabbat]] even if the food is fully cooked and is very hot since an oven is considered an uncovered flame, Hachzara is forbidden. <Ref>Shemirat Shabbat KeHilchata 1:17 </ref>