Thermos Flask on Shabbos
Question: I forgot to put my Shabbos kettle on before Shabbos so took a thermos flask to my neighbours to fill up, though they thought it could be an issue of hatmana . Can one fill such a flask on Shabbos? Answer: The Gemara (Shabbos 51a) teaches that the issur of hatmana , insulating foods on Shabbos, only applies to the pots in which the food was cooked, though not to any container into which the food is dispensed. As one knowingly cools the food by transferring the food, it is unlikely that one will then heat the food. Rashi explains that by transferring the food, one demonstrates that they don’t mind if the food loses a little bit of its heat. One would, therefore, be able to insulate the second container. Rambam (Shabbos 4:5) explains that chazal only prohibited insulating the food in the pot in which it was cooked. The Shulchan Aruch (OC 257:5) follows Rambam. R’ Moshe Feinstein (Igros Moshe OC 1:95) writes that according to Rashi, one may not be allowed to transfer hot ...