Fortunately when the call was received the "Rav" was taking his beauty nap. "Fortunately" because he didn't know the answer to the question.... Unfortunately, because I'm not sure it helped [the beauty nap].
:-)
But after Shabbos he searched around a bit and found out that not surprisingly it's a machlokes haposkim. Many say it's "molid" - creating something new, from liquid to foam. For example, some poskim hold that it is forbidden to make solid ice from liquid. Or to use toothpaste which turns the paste into foam.
Others say that the change is not significant enough and it is therefore permitted.
I thought about how we permit woman to use liquid soap and wash dishes even though it also turns into foam from the original liquid. Not only that - we EVEN permit MEN to do the dishes. Growing up I had it easy - a dishwasher. No! Two dishwashers! As they wrote to me tonight in 2 separate emails - AHHH! [Which is interesting because just a short while ago I was learning my beloved Yabia Omer [vol. 10] and he discusses whether you need to have separate dishwashers for meat and milk. But he doesn't say AHHHHHH. Unless he is having a throat culture. Don't you hate that. He says "Open up and say AHHHH". You do as he says, he sticks some wood down there and you almost choke. Then he smiles and says "All done".]
So if you ask your Rav like the can said and he tells you it's a machlokes THEN what do you do??
I guess you buy a can of whipped cream that doesn't raise the problem??
