Dear Nathalie, Welcome!
I live on the Outer Banks of North Carolina, on an island which is less then 1/4 of a mile wide and 60 miles long. I am surrounded by water! I live in humidity. The good thing, friends tell me it’s good for your skin and keeps the wrinkles away! The band news: It’s very difficult decorating cakes, but it can be done. Right now, at 10:46 p.m. I am looking at 76% humidity and the temperature, is 78*. During the day time we get up into the 90’s with humidity staying at and around 80%. Recently, I found this blog here on Cakes Decor and I have adjusted the buttercream recipe. http://cakesdecor.com/sugarpixy/blog/169
I have been very successful with a knock off of this buttercream recipe.
If you look around the web or watch youtube videos about fondant or gum paste, they will tell you to not use corn starch. I find I have to use it. I used it in the buttercream, along with the meringue powder, and it gave it the icing more stability and crusted nicely.
I use a little bit of cornstarch with my fondant (MMF) and it keeps it from being so sticky. If I use confectioners sugar, I have to use so much, the fondant starts to crumble and it is very difficult to cover a cake with it. I have had success with commercial fondant and gum paste and using it in a 50/50 mix of fondant and gum paste.
I also have an air conditioner in the commercial kitchen where I decorate my cakes. It is adjacent to a burger restaurant where people are in and out and once they start the french fryers and grill, the humidity and heat in the room gets higher. Luckily there is a door between us and I almost insist the door remains closed while I am decorating cakes, especially if I am attempting to stack wedding cakes. We have a lot of tourists who come to the restaurant and insist on standing with the front door wide open. (The resturaunt has air conditioning also, but between the burger grill, french fryer and the front door being left open, it gets close to 100 degrees behind the grill!)
I am very thankful to have my commercial space and I try to not complain about the heat.
I hope to one day have my own bakery shop. It will have an awesome air conditioning system. amazing stereo system, and a fancy private seating area for brides during their tastings. Hey, a girl can dream, can’t she?