Use of a thermos on Shabbat

Hi,

One may not insulate food on Shabbat, wrapping its receptacle in order to preserve its warmth. Nonetheless, one may place hot food in a thermos on Shabbat.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 1:95)

Have a great day,
Mordechai

Having a non-Jew help with heating up food on Shabbat

Hi,

If a Jew is not permitted to place food on a hotplate or blech due to the laws of Shabbat, he is also not permitted to have a non-Jew do it on his behalf, and food heated up in that manner would be prohibited.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 1:94)

Have a great day,
Mordechai

Putting dry food on a hotplate on Shabbat

Hi,

One may not take food from the refrigerator and place it on a hotplate or blech on Shabbat, if the heat in that spot is high enough that food left there indefinitely could reach a temperature in excess of yad soledet bo [approximately 113 degrees Fahrenheit]. This includes food that does not contain visible liquid.

Note that the laws of heating up food on Shabbat are complex; please do not rely on these simple emails for practical rulings.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 1:94)

Have a great Yom Tov,
Mordechai