I have had this happen to the last two cakes that I did. I end up with a bubble, just like a fondant bubble on the side of the cake. Anyone know what is happening?

Is this a cake that has been frozen? (more details will help us help you figure out what happened!)

from watching sugarshacks buttercream dvd she says that may happen if there is moisture on the cake (it feels sticky when u touch it) and u put the buttercream on it....

This is caused when the cake was cold and has warmed to room temp. It shrinks a little and causes gas to form under the buttercream, which causes a bubble. I agree, moisture builds up under the buttercream as well Especailly with a crusting buttercream as you are sealing the bc.

I assume you are icing your cakes cold? Perhaps letting them warm to room temp before icing woud work.

I have heard that putting a few drops of white vinegar in the buttercream helps too, but I havent tried it.

I think the best fix ever is to use IMBC. Never seen it bubble up.

I've heard them referred to as cake "farts". Let your cakes rest before icing so they are not moist to the touch. I had serious problems with them. I wanted to make sure my cakes were moist but in my own referrence, I need to let them become less moist to the touch. Not so much of a problem now. HTH

what is IMBC?

I have this happen to my BC cakes pretty often. My cakes are never "cold" when I apply the BC. I always freeze my cakes after baking, but I always allow them to thaw covered for several hrs (@ least 6hrs). I fill my cakes & crumb coat and after they crust, cover with Saran Wrap & let set. I place a same size cake pan on top with a wgt to increase the settling process. I let them settle for 2-3 hrs. It would probably be better to let them settle longer, but I usually don't have time. Before I put the final BC coat on, I unwrap the cake & let air dry.

I think (I may be wrong) that my problem is the use of the large icing tip that i use to apply the BC before smoothing. It may create air btw the BC & the cake.

The cake "farts" aren't really a big deal to me anymore. I usually notice them right away with smoothing, and remove them by piercing through the BC & into the cake with a small skewer. After I make the small hole, I smooth in opposite directions with a Viva towel and fondant smoother. The air is released and it's barely noticeable if you smooth enough.

I've had it happen and the cakes were never in the fridge or freezer at any time, so I don't think it always has to do with cold cakes.

I've had the same problem!!! I've almost given up doing wedding cakes because I have that problem every time!!! I once left from setting up a wedding cake and then was told that a bubble appeared and got big enough the icing fell off!!!!!!!!

Someone mentioned IMBC icing??? Is it a crusting type of icing???

I think this has to do with the cakes settling. I always let mine rest over night but was still getting these buldges. Now I rest a tile on top over night and haven't gotten one in the past few cakes. HTH.

I too have a cake gas problem and thanks to the CC community, learned to let the cake rest for a while. I'm still not confident I wont ever have them, but know what to do when I do get a bubble (Have a large pin to pop the side and poke an airhole on top while it rests and fix the holes before I decorate or fondant)

I do let mine rest... I stack the two layers and then wrap them in saran wrap and put in the refrigerator over night....??