After icing a few six in. cakes I set them aside. I came back later to decorate them and noticed a couple of them had bulges on the side.

I thought maybe it was either that the icing was sagging or the cake underneath was sagging. When I pushed on the icing, I noticed it was more of an air pocket. I pushed on it gently but it would just bulge back out. Then I took a toothpick and "popped" the bulge and pushed it back in. I've never had that happen.

Anyone know why it happened?

Hi, about the bulges----------did you have a filling in between the layers? Sometimes if you don't put a rim of BC around each layer before filling, the filling will creep outwards and cause a bulge. Also, I ice my cakes when they are firm cold, crumb coat , chill, then ice again. Hope that helps.

Was your icing "wet" than usual. That has happened to me twice and ALL the time at a bakery that I use to work at. Popping the bubble with a toothpick is best but the part I dont like is the wrinkle look that is left after popping it. The last time that happened to me, I had put in a little too much liquid in my icing. So I figured that that is what happened. The icing is sweaty or "wetter" and I need to watch my liquid when adding water to the icing while I am mixing it.

i always let my cakes sit for a bit after stacking and crumb coating (at least an hour or two). They are able to settle and won't move once I put on the final coat. it seems to prevent what you have described.