I've just started using ganache under my fondant to get the crisp lines. I have a couple cakes coming up and wanted to know how it would hold up in our hot, humid summer weather. So, I made a couple test cakes, filled AND crumb coated them with caramel buttercream, let them crust and then I covered with semi-sweet chocolate ganache using the 2:1 ratio -- made it the day before so it had thickened. I left them on the counter to set up overnight and came down this morning to these...(I put them into the fridge before I took the pics).
It's not a terrible tragedy since they are only test cakes (besides the waste of good cake and chocolate)
But what did I do wrong??? AND how do I keep this from happening to the client cakes I have coming up?
Am I not supposed to crumb coat with buttercream before the ganache? It has been terribly humid lately but I need to plan for that anyway because that's our normal weather for the next 4 months.
I planned on covering these with mmf, so I'm struggling with knowing how to store these guys after they're decorated..fridge?? counter??
HELP PLEASE!! 
It looks like the filling is bulging out of the cake. This would be a problem no matter what you covered it with. Correct the bulging problem before you go further. It is not the ganache.
I only ganache my cakes, never buttercream. I am thinking it could be the buttercream under the ganache that has caused this to happen, as I have never had that happen just using ganache. Does your chocolate have a cocoa butter content of about 50%? If not it could be that the ganache is not firm enough. It is very hot and humid during the summer here also and on particularly hot weeks I chill the room temp ganache for at least half to an hour to firm it up before using. I also refrigerate the ganached cake. It is a bit tricky and requires some testing to see what works for you, depending on how bad the whether is I sometimes fondant the cake straight out of the fridge and then put it straight back in again, especially if the temp is up around the high 30's celcius (not sure what that is in farenheight but think swelteringly hot). If it is not too bad temp wise, I ganache the cake (no buttercream crumb coat) and put it in the fridge for about 1/2 hour before I fondant it, this helps the outside coat to firm up enough to get sharp edges.
Thick dam for filling, no buttercream crumb coat -- just the ganache as crumb coat, refrigerate after ganache. Got it! 
What about after the fondant? If I put it back in the fridge after decorating, it's gonna sweat like crazy when it comes out..do I risk it and just make sure it has enough time for the condensation to evaporate or would that be bad for the ganache underneath? Or should I refrigerate after covering with fondant, take it out, let the sweat evaporate and then decorate?
Thanks for all the info, I really appreciate it!
Yes, only ganache, no buttercream. When I make my dams, I make it so thick it is practically like fondant, I have to roll it out in a snake. It might take a little extra work, but I have never had any bulging and that makes it worth it to me. HTH
Your post says you crumb coated with caramel bc. When you use ganache you don't crumb coat with bc. You just use the ganache to crumb coat and ice. And with a soft filling you need a good dam inside to hold it in.
This test cake will still be yummy.
this is exactly the way I ganache my cakes too and fill...I never use a bc crumb coat.
Yes, only ganache, no buttercream. When I make my dams, I make it so thick it is practically like fondant, I have to roll it out in a snake. It might take a little extra work, but I have never had any bulging and that makes it worth it to me. HTH
great idea about the dam being so thick. do you use a powdered sugar bc for the dam?
to the OP- I think you can just strip off the ganache and crumb coat on these cakes and redo them in ganache only- seeing that they are practice cakes.
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