I made a cake last week in which I covered a 12" round with fondant. I used cream cheese buttercream on the cake and covered this with one large piece of fondant. It went on beautifully and smoothly and had no small bubbles or imperfections. Then later in the day, the fondant began bubbling up- literally lifting right off of the BC. Not just a small spot either - almost half of the top of the cake. Anyone know why?
Was the cake cold when you covered it with fondant? Sometimes cold air trapped inside a cake can expand as it warms and cause bubbles.
how did you attach the fondant to the icing?
I read/heard somewhere that if your fondant isn't completely stuck on to the cake it gives the opportunity for air bubbles to happen.
this happened to me once, and it looks like a thing from a horror film! like what is underneath that fondant!
now i spray my whole cake lightly with water and make sure that the fondant is really sticking on to it when i smooth it out. HTH
sometimes when the bc crusts out from being left out too long it doesn't leave a sticky surface for the fondant to attach to...it may also be due to temperature. the best way to get rid of the bubble is to pin prick it and smooth the bubble out.
i have gotten in the habit of poking a vent hole in the center of the top of my fondant cakes. when i get air bubbles under my fondant i can usually smooth them towards the hole, or i will poke another needle hole at an angle in the bubble and smooth. I also always ganache under my fondant, or use a super solid cold SMBC, so it is easier to create a seal under the fondant.
I did poke a vent hole and it eventually bubbled up again! So weird! I think next time I'm going to try the water spray tecnique.