I live in MN and during the summer it's very humid. The last 2 months it's been between 90-100 degrees every day. I have air conditioning in my cake studio which I crank down to about 68 degrees, but I still have issues with my buttercream cakes wrinkling. Everything looks fine when I finish icing the cake. I put it in a cake box and leave it sit on the counter overnight. Then when I come in the next morning, it's all wrinkled. I know this has been discussed in previous posts but it seems like no one's been able to come up with a definitive answer as to why this is happening, what causes it and how to fix the problem. Can anyone help me? This is sooo frustrating because it's affecting almost every single cake I do now. I'm using a modified version of Indy Debi's buttercream. Here is the recipe I use (I like to use real butter versus shortening in all of my frostings):

3 sticks of butter
1 envelope Dream Whip
3 tsp vanilla
2 Lb powdered sugar (C&H)
approx. 1/3 cup whole milk

I can see what your are referring to I think more infor might help.
Are you icing COLD cakes?
Could the cake still be warm?
Is the icing at room temp?
Are you pressing the icing onto the cake enough? (But this really doesn't look like that problem to me.)
The only thing that comes to my mind is maybe cut down a bit on the liquid in the recipe.......?

Here is what I typically do with my cakes:

1. Bake them and cool completely
2. Fill them, let them settle for several hours with ceramic tile on top for weight or overnight
2. Freeze them for a day or two (wrapped in saran wrap & placed in freezer ziplock)
3. Pull out of freezer night before I'm going to ice them - so they are at room temp when I do ice them (still wrapped up)
4. Unwrap cake the morning I'm going to ice it
5. Mix up buttercream, then ice the cake. Buttercream and cake are at room temp.
6. Place iced cake in cake box and leave on counter overnight (air conditioned in the shop)
7. Next morning the cake is wrinkled

bump..I'm curious to know why too! Anyone?

I have never had this happen personally, but I was thinking that if this only happens during the summer it might have to do with the air conditioner. You said you set it at 68, when you are finished decorating the cake and it is in the box turn the air conditioner up to 73-74. The job of an air conditioner is to cool the air and suck out the moisture in the air. Maybe it is removing too much moisture from the air and your icing making it wrinkle. Because it will suck the moisture out of everything and anything. I find my plants dry out faster in the summer with the air on then in the winter with the heat on.

Give it a try it can't hurt. I have my air conditioner at 74 to 75 to keep the humidity out of the house, any lower makes it too dry. But I haven't had that happen to me.

Good Luck.

I think the butter can't stand up to the heat. Have you tried 1/2 butter and 1/2 hi ratio shortening? Personally, I use all Sweetex to handle the high heat here in Texas. Good luck.

I live in Houston where it is alllllllways very humid. I have had the same problem with my icing and found that adding a little heavy cream to my recipe helped. What has made the biggest difference though is not shaving the edge off of the cake prior to icing. Sometimes a little trimming is necessary to get the sides straight and that seems to be when the wrinkling occurs. Hope that helps a little!

i used to have this happen with an all shortening buttercream. I have never used an all butter icing, but once i switched to hi ratio shortening it stopped.

You don't mention how long you leave the cakes unwrapped once you have defrosted them but before you put on the butter cream. If you do not leave them unwrapped long enough for condensation to dry off, the butter cream can buckle and wrinkle because there will be a moisture layer between the cake and the butter cream. Don't know if that is your issue, just thought I would throw it out there for your consideration.

........ If you do not leave them unwrapped long enough for condensation to dry off, the butter cream can buckle and wrinkle because there will be a moisture layer between the cake and the butter cream......

She is leaving them on the counter (room temp) overnight so there should not be a condensation problem - it would have had ample time to dry up. Also if they are wrapped condensation will not form on the cake but on the wrapping. I really don't think this is a moisture problem - at least not like condensation........
Now the thought of the air pulling too much moisture out of the air is thought provoking

I have an odd mind so here's my theory. When you take your cakes out of the cake pans, do you run your hands over the surface of the sides of the cake to "sluff off" all the loose crumbs before you crumb coat. Try it and see if it makes a difference. If the icing is stuck to the sides of the cake it won't move but if the crumbcoat is riding on the surface of large crumbs, naturally it will appear to be wrinkled.

I live in GA and also have this problem on round wedding cakes. My solution: Put your finished cake in a large box (larger than cake). Put a glass of hot water in the box. It should be steamy but not boiling. You don't want to melt the icing, just keep it a little humid. Be sure the water won't tip over. Seal the box up tight or put a plastic bag over the box. It should still be pretty the next morning.

This may not be the solution for you because I don't use your recipe. I use an all shortening/ crusting buttercream. My theory is that the cake shrinks or settles a little overnight and if the icing is already dried, it wrinkles. You might also be putting the icing on too thin. HTH!