Cake Blow Out

Decorating By kendra_83 Updated 26 Sep 2013 , 1:33pm by kendra_83

kendra_83 Posted 22 Sep 2013 , 2:30pm
post #1 of 9

Lately, I've been experiencing blow outs on my fondant-covered cakes.  Here's my process:  I fill my cakes and let them sit on the counter overnight to settle.  I refrigerate them until they're solid and then I ganache them.  I let them sit in the fridge for an hour or so to set up my ganache and then try to let them come to room temperature before covering in fondant.  Last night, I came home to a decorated and finished (I thought!) cake that had been sitting on my counter with a gigantic air bubble that caused a huge crack down the side.  Thankfully, I could hide it with more decoration but I'm wondering what causes this in the first place.  I've noticed that it happens more often with the change of seasons.  Is it the temperature change?  Is it humidity?  How do I avoid this in the future?  Any tips or advice would be greatly appreciated.




8 replies
CakeGeekUk Posted 22 Sep 2013 , 3:05pm
post #2 of 9

Hi Kendra, I'm not sure about the weather implications since I'm in a cooler part of the world.  The only advice I can think of is to make sure you don't trap any air bubbles when you're laying on the fondant. Make sure any air pockets are released before smoothing out the fondant. Check the cake again an hour or two after icing and if there are any air bubbles forming at this stage deflate with a sterilized pin and smooth over.  I hope you get to the bottom of it anyway.

kendra_83 Posted 22 Sep 2013 , 7:33pm
post #3 of 9

Thanks.  Although, I've had air bubbles under my fondant (which I can deal with), these are coming from under the ganache and don't surface until hours, sometimes days after the fondant is on.

costumeczar Posted 22 Sep 2013 , 7:49pm
post #4 of 9

It's usually air that's trapped between the layers if you've got gaps in the filling and pockets happen. Of if you don't have the ganache pushed up into the space between the layers. If you fill the cakes, then push down firmly on the top layer to force any air out, then make sure to really fill the space, you'll have less likelihood of it happening, it can happen with temp changes if the air warms up and expands, too.


When I cover cakes with fondant I let them sit at room temp for a few hours to see if anything is going to happen before I start decorating them. If you have a cake that is cold and you let it warm up air can expand and try to get out, so keepign everythign at room temp the whole way through is a good thing to do. Iknow that a lot of people cover everything when they're cold, but if you do that jsut let it sit for a longer time before you start decorating them.


Another way to let hte air out, if there is any, would be to poke a hole in  the areas on the cake that are going to be covered with decorations. This won't work on cakes that are totally smooth, but you could poke pinholes in those. Just creating a little hole that the air can vent out of can prevent anything form going on.


Also, make sure the bottom of the fondant isn't totally adhered to the cake, and that air can ooze out the bottom if it wants to.


Here's my cake tumor article:

kendra_83 Posted 22 Sep 2013 , 8:21pm
post #5 of 9

Wow!  Thanks so much costumeczar for your suggestions.  Your articles are great - very descriptive & detailed.  I'll definitely try your suggestions.

AZCouture Posted 22 Sep 2013 , 9:16pm
post #6 of 9

AHey Kara, since I know you use both abc and imbc depending on your project, do you find that you have those troubles when working with the mbc's? I never have bubbles or cracks,etc, have to attribute it to the mbc.

costumeczar Posted 22 Sep 2013 , 10:23pm
post #7 of 9


Originally Posted by AZCouture 

Hey Kara, since I know you use both abc and imbc depending on your project, do you find that you have those troubles when working with the mbc's? I never have bubbles or cracks,etc, have to attribute it to the mbc.


I've had it happen when the cake is covered in fondant and when it's covered in the confectioner's sugar buttercream, but I don't remember if it's happened with the IMBC or not. I don't see why it wouldn't because there's no reason that the IMBC would prevent a bubble if fondant wouldn't...I think it has more to do with the temperature of the cake when it's covered than it does with what you're covering it with. I'd be willing to bet that the fruitcakes that are baked in a solid 3" layer are less likely to develop a bubble than cakes with two layers and a filling. Just my guess.


I bet the meringue buttercreams wouldn't develop the cracks, though, since I think that's probably a shortening thing. Again, just a guess.

LianaLapadula Posted 25 Sep 2013 , 7:26pm
post #8 of 9

I've had this happen when there are actual fruit slices (like strawberry slices) or fruit flavorings in the buttercream in between the layers.

I'm not sure if you had fruits in the cake.

But I believe it has something to do with the acid in the fruit that creates gas which in turn creates air bubbles in not only just under the fondant but also under the ganache.


Hope this helps.

kendra_83 Posted 26 Sep 2013 , 1:33pm
post #9 of 9

There was no fruit inside the cakes but I think I've figured out a solution with some help from Kara.  I put a really good ganache dam between the layers, pushed down really hard on the cake to eliminate most of the air, filled in all the gaps and low spots with ganache, filled in the space between the cake and the edge of the board with ganache and let it settle on the counter overnight before chilling and finishing up the ganache coat.  No bubbles so far!

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