Question:
Can I use a hot plate with a thermostat (of the commercial buffet server kind) to keep food warm on Shabbat? I have heard that it can be a problem that removing the food could cause the activation of the thermostat.
Answer:
Hello,
I consulted with R’ Haperin shlit”a from Machon Technology V’halacha, and he said that what you heard could very well be true, however it isn’t always true, and it would depend on a number of factors. He said that it is better to use a hot plate that doesn’t have a thermostat, however if you have no choice, then you should do the following. If the hotplate has a light to show when the heating element is working, then only take the pot off when the light is on and show that the heating element is on. If it doesn’t have a light, and you can’t tell when it is on or not, then you may take the pot off the hotplate. (His psak is based on various factors). You should not do return any pots, however, to the hotplate.
Best wishes
