Sous Vide—Tevilat Keilim and Warming Food on Shabbat
QUESTION
New York
Two questions regarding a sous vide:
1) Does it require tevilah?
2) Can it be used to reheat food on Shabbat, assuming it is on and in heated water from Erev Shabbat?
ANSWER
1. It does not require tevilah. It does not come in direct contact with the food (plastic bag and water both intervene). (Shulchan Arukh YD 120:4, Arukh HaShulchan YD 120:32, Sefer Tevilat Keilim, 1:4 ft. 7)

This glass mug by Bodum has a rubber stopper at the bottom that is designed to allow the air trapped between the two layers to expand due to heat but to not let water in since the water would get trapped inside. Can it be toveled/is the rubber a hatzitza? It is designed to be there and be left in place, so would it be considered to be eino makpid? (