Hello fellow Cakers! I've been using Indi Debi's buttercream recipe for awhile now, but lately have noticed after a day it has an alcohol aftertaste. I haven't changed any of the ingredients. Could it be from sitting in the mixer bowl? I have a 20qt mixer. I've been using an clear imitation vanilla flavor from CK Products. Has this happened to anyone else? TIA!!

I could be the vanilla. I have found that the clear vanilla, whch as you say, are not real vanilla, can often have a really strong alcohol taste, and not the good kind. I realize that often one wants a pure white icing, which is why we use the clear vanilla, but I find that for the amount of extract I might need, it doesn't make the icing look too off white. And the taste is way better.

Agreed, it's probably the vanilla. You can make vanilla extract by putting vanilla beans/pods in alcohol, so that would make sense.