I mainly make chocolate decorated cakes but recently have lots of fondant covered cakes. I have had real bulge problems recently and cant work out why. I recently posted about bulge and have now started resting after filling my cakes.

Last week I used perfectly straight cakes used butter cream equal quantities of unsalted butter and icing sugar. Then I weighed them down with a weight to settle for about 3 hours it bulged and i scraped the bulge bit off and smoothed again. Then refridgerated for about an hour and covered in fondant. The next morning bulge!!!! AHHHHHHHHHH why is this? could my hot kitchen do this? Our place is very hot and there is no cooler room this week its been up to 30 degrees in there so quite hot. Is this the cause of my bulge? would a cake spackle help?

i believe that it is an air bubble expanding as it heats up...i have had trouble with this recently too.

you have to make sure that the buttercream under the fondant is prefectly smooth (i sometimes add a few coats letting each one cool and harden before adding the next) and apply the fondant in a way that prevents air getting trapped (working you way from one end to the other easing out any air as you go).

if you put the cake in the fridge and then cover it then i think it will only make the problem worse as the cold air will expand and bulge even more. if anything you want to keep the cake cool AFTER you have covered it not before.

Hi Steve

Its definitely not an air bubble. I can see the layers of buttercream under the fondant so the buttercream is definitely bulging out. driving me mad

My personal observation is that bulges are related to any, some, or all of these factors:

Too much filling
Too soft a filling
Too thick cake layers
Too soft icing
Not enough settling time after filling
Too thick fondant adding a lot of weight
and, yes, the cake being kept too warm after filling

30C (86F) is very warm for storing a cake. Surely the cake, the filling, and the icing are all reacting in different ways to being so hot. If you covered that cool cake with fondant and then let it sit at room temp, surely it would begin to "wilt" in the heat.

My solution to bulges it to always torte my cake layers, so that 4" cakes have 3 layers of filling. I don't stack 2, 2" layers with one layer of filling--those always bulge badly and I think it's because the top layer of cake is just too heavy.

Pro bakers often bake up 1" layers of cake in sheet pans, cutting rounds from that, and so a 4" cake, for them, is 3, 1" layers of cake plus 3, 1/3rd inch thick each layers of filling. My cakes are more like 4, 3/4" layers of cake with 3, 1/3rd inch layers of filling.

I allow my crumb coated cakes to rest, scrape out the bulge, and ice. My cakes probably never go above a room temp of 72F.

I've used cake spackle when I need a really crisp edge on a cake. It does help. If you really can't keep the cakes cooler after decorating, using spackle won't hurt & might help.

Rae

Since you said 30 degrees you are obviously not in the US, we use Fahrenheit. In the US almost everyone has air conditioning, you may want to invest in a small window air conditioner if you think the kitchen heat (and other rooms as you say) is causing the problem.

nope in the uk! unfortunately in a basement with no windows and no way to extract heat from air con. do you think the heat is causing the buttercream to soften too much?

ah so will trex be firmer? is the taste good enough?

Yes, the melting point of Trex is much higher than butter.

Try a small batch to see if you're happy with the flavor & texture. You can tinker with the ratio of Trex to butter to get what you like. You can also add a bit more vanilla, if you like.

I live in a cooler area of the US and in the summer months, I often use at least 1/3 vegetable shortening + 2/3 unsalted butter. I find that it helps a lot.

Rae

this is all excellent guys. maybe i will have to coat the cakes at home, but space is a premium there! I notice in the usa you guys use what look like tubes at cake dowels when you stack them. here we use the plastic sticks although i hear we are getting the more tube like one. Do you know what they are called?

We use lots of things for stacking, but I really like fat straws, called bubble tea or boba tea straws. I'm sure you can find some at the many Asian markets or take aways in the UK.

They're easy to cut and have the benefit of the hollow cylinder--much stronger and stabler than a solid wooden stick dowel.

Wilton also makes hollow dowels. They're very thick walled and a bit harder to cut, but work nicely.

Rae

thats interesting someone recommended straws. my fear was any sideways force ie when delivering could cause the straw to buckle? they are strong enough even for say 4 tiers?

No, sideways force causes solid stick dowels to shift sideways=collapse.

The hollow cylinder is much more stable and stronger than a solid stick. Try to crush a straw lengthwise between your palms---you can't.
Also, you aren't displacing any cake with a straw, but you ARE with a solid stick. The plug of cake in the bottom of an inserted straw is also an added stability benefit.

Yes, you can stack a 4 tier using heavy duty straws.

Rae