Hello fellow cakers, I have searched and searched the forums but I haven't found any responses that fully satisfy, so I'm going to raise the question again. I am an experienced professional, self-taught, www.SensationalCakesAndMore.com. The cakes look great, except... GOITERS! LOL, that's my name for the sometimes HUGE air bubbles that appear out of nowhere on a finished buttercream cake after standing several hours or overnight. Same problem when using buttercream under fondant. I have tried the following techniques to avoid them:

1. Jessica Harris' techniques (i.e. remove cake from pan while still warm, refrigerate with a pound or two of weight on it, stack tiers, refrigerate with weight)

2. Freeze layers, then fill, weight overnight

3. Minimize air bubbles in buttercream (avoid overbeating), take care while filling/icing to avoid trapping air between the icing and the cake

Yet I'm still seeing these AWFUL AIR BUBBLES frequently, like maybe 15-20% of the time... far too often!! I want to figure out how to prevent them, not just get rid of them after they occur. I'm trying to figure out if the excess air that's yearning to escape is from the cake, the icing, or the technique I'm using to fill/ice. I came across a suggestion this morning to poke a hole straight down through the whole cake to give any trapped air an easy escape route, then patch it while finishing. I'll try this, but still looking for more...

Can anyone provide tried-and-true solutions, or even scientific explanations for this phenomenon? I'm embarrassed as a so-called "veteran" to still have this problem, but I figure I can't be the only one, so I'm hoping y'all can laugh at me then show me the error of my ways! 

I call them cake tumors, haha!

First, I would think that freezing anything while it's warm would trap air in them. The bubbles are cause when air warms up in the cake, whether inside the tier itself of in between the layers, and starts moving toward the outside. Air expands when it gets warm, so my guess would be that your best bet to get rid of air pockets would be to keep everything at room temp.

I hardly ever get a cake tumor, and I pretty much do everything at room temp, other than refrigerating the finished cake once it's decorated. I don't freeze anything and if I did I would let the cake warm up to room temp before working on it. You want to equalize the temperatures...

Another thing that seems to help is to let the iced and not-yet decorated cake sit at room temp for a couple of hours before decorating. If something's going to appear that would give it time to do so, then you can deal with it before decorating.

So to give you an alternate routine to try, I'd cool the layers COMPELTELY (overnight is best), fill them and crumb coat, then put something heavy on top of it to really press it down. That part would be optional but I find that it gets rid of any air pockets that were left when you fill the layers. I just press down on them hard with my hand, I don't use books or boards or anything, I just give them a good press. Then either wait a while to let any bubbles come out before icing, or finish coat the tier and let it sit for a while.

No matter what you do you might get a bubble, though, you can't always fight the laws of physics.

I am unsure what causes this.  I've seen people suggest all kinds of methods to prevent...and i've never tried any of them, yet I've maybe had a bubble twice in the last 10 years.  I ice my cakes straight from frozen then let them "thaw" in the cooler, all the while they are in and out of it being worked on, but still never had an issue.  So I really have no suggestions here.  Maybe someone else's suggestions will help.

Thanks you two. I've been suspecting it has something to do with refrigerating or freezing. In the old days when I didn't have 4-5 fancy cakes a week for this one-woman show I did everything real-time and had no need to freeze cakes. To maximize my late-week decorating time I've taken to making the layers ahead of time and freezing, so I've been exploring the different ways to make that work, case in point Jessica's info. Czar, I'll try your suggestions and see if the incidence of goiters - tumors! love it - is reduced. It's infuriating.