My cakes are completely thawed and are iced with a buttercream type frosting. I don't use a crumb coat. I use the Wilton icing tubes and once the icing has crusted use the Viva paper towel method to smooth the sides. If I travel with the cakes, sometimes the icing comes away from the sides of the cake creating a bubble. I usually can apply some pressure to remove the bubble, but I can't figure out what is causing this. Any thoughts or solutions would be greatly appreciated.

There are so many theories as to what causes the bubbles. I'd love to hear opinions from other CC members. I've heard frosting cold cakes with room temp BC, fruit fillings causing air pockets, etc.

All I know is that air somehow gets trapped. I just deal with it (as frustrating as it may be). I poke a hole, pop out the air, press on the sides of the spot & repair the hole.

Anyone know? Anyone?

A long time ago Sharon Zambito theorized that the blow-outs occur when the sides of the cake are too moist. I used to let my cakes cool in the pan when I was busy and would ice them right away, while the crust was super moist, and I would have blow-outs every once in awhile (even under fondant).

Since reading her theory, I now let cakes sit out on cooling grids for the sides to evaporate excess moisture and have not had this problem happen again. I do this when I let cakes cool in the pans and when I freeze/thaw cakes. Haven't had a blow-out in a couple of years now.

All hail Sugarshack!

Are you settling your cakes with a ceramic tile or a book? I stopped having blow-outs since I put a book over my cling-wrapped and filled cakes and leave for at least 3 hours to settle. All the air in the cake gets pushed out. Leah_s posted this advice on CC and it has been working for me ever since. You can trace back her posts on settling a cake or PM her.

I use a side icer tip to ice the sides of my cake. I found that doing so and then smoothing the sides does not attach the icing to the cake enough. I would have problems with blow outs and/or the icing pulling away from the sides. Now I use a pallet knife to push the icing against the side after using my side icer and then start using my smooth to remove excess icing and smooth the sides. That has cleared up the problems I was having.

If they are even slightly cold this will happen. I ice all my cakes at room temperature and this never happens. The one time it did happen was when the cake was a little cold and the condensation was causing the icing to come away from the cake. I should also mention that I only ever hear of this problem with American style buttercreams, not Swiss or Italian meringue buttercreams.

The tile trick is mainly for the bulge, but if its working to prevent bubbles, even better. I also posted (several times) about a trick my chef-instructor taught me in culinary school., After the cake is iced on the board, take a palette knife or thin knife and run it between the bottom of the cake and board to "break the seal." I've also read that some people poke a skewer into the top of the cake. The hole will be covered by the next tier. Both methods let air escape.

Thanks for all the great advice!