When someone wants to heat up a piece of kugel on Shabbos by putting it on top of the hot water is it a problem to wrap it up completely in tin foil before putting it on the hot water?
Answer:
There is a problem in wrapping up the kugel entirely and placing in on a source of heat. See Iggros Moshe Orach Chaim 4:74 (hatmanah 3) who prohibits placing kugel completely wrapped in aluminum foil on top of the cholent pot cover.
Therefore, the foil should be left partially open.
