Hi, I am fairly new to cakes and I have been asked to make a wedding cake this August that will be held outside. Now when I say outside, I mean SETX weather. Hot and very humid. I warned the buyer about cake and outside not being a good match. Would commercial fondant hold up some what? I make my own, but I do not trust it as much as I need to for this challenge.
Any tips or advice would be so helpful and muchly appreciated.
I live in the tropical weather capital of the world, but I'm originally from Houston, so I get where you're coming from. When I use fondant, whether home-made or ready-made, I always prepare it with 1-2 teaspoons of CMC and 1-2 teaspoons of shortening per pound of fondant. I also knead in some extra powdered sugar if it looks like it needs it. So far, things have worked out pretty well with these tweaks.
The fondant is not likely to be the problem. It's what's underneath the fondant that will start to melt, falling away from the sides of the cake and making bulges in the fondant.
An outdoor reception in August in TX is nuts. I'm not suggesting you repeat that to your customer of course, but it's a bad idea.
What about a dummy cake? Especially if you put the fondant on a couple weeks in advance and let it harden, it would be very unlikely to melt as long as the faux cake was sitting in the shade. Then make kitchen cakes and keep them indoors somewhere until it's time to serve the cake.
I guess I should have read the OP's post a little more carefully. I kind of glossed over the part that said "outside". Nothing will hold up outside in Texas in August and you're risking food poisoning as well as a cake that falls apart. Texas_Rose is, as usual, right on the mark.
Those bulges will be there no matter what...I have tried all kinds of buttercream to prevent that-buttercream on its own might have a better chance, but under the fondant it is like a sweatshop. Not worth the risk. Good luck!
I generally use ganache under my fondant, because it holds up slightly better than buttercream in the heat. And I use the thinnest possible layer of ganache, because of the amount of humidity that the underlayer adds to the fondant. I mean, when I first made cakes here, I had the fondant sliding down the sides of my cakes - a truly unfortunate spectacle (although fortunately it happened on family cakes, not ones for customers). My cakes will hold up in indoor settings cooled down only by ceiling fans, but my daughter's baby shower last year will attest to the fact that nothing will hold up outdoors in August! The topper and the top tier slid right off the cake! My granddaughter's name is Ana Paula, but the cake ended up being for a Paula, whoever she is.