I have an outdoor cake in August. It is fondant-covered. I usually use IMBC but have recently converted to mostly using ganache under fondant. I'm going to watch the forecast like a hawk (of course) but I'd really like to know from those who do white choc ganache/fondant - up to what temp. would you feel comfortable leaving a white ganache/fondant cake outside in? 80? 85? I know the melting point of white choc is low 90s so if it is that hot I'm going to use Indydebi's buttercream.
Anyone with experience care to share?
Maybe someone else will be able to help you more as I haven't done a lot of white choc ganche in the heat particularly outside but if it is really hot I wouldn't use the white choc ganache, when I did a cake course in Dec it was really hot and the business where I did the course actually had a problem with one of their cakes because the white choc ganache became too soft (I think the venue they delivered it to wasn't A/C'd) and it started to collapse. They said that on the rare occasions they have had a problem it is usually always white choc ganache
On the other hand I did a cake with white choc ganache under fondant a couple of months back where they placed it right near a glassed wall and I was worried the sun coming through the glass would be a problem and it turned out fine (although it wasn't super hot that day).
Good luck with whatever you decide.
I only use white chocolate ganache under fondant in all weather. It can get pretty hot here, our summer can be 35 degrees celcius which is about 90 something on your fahrenheits but I have never had a problem with my cakes outdoors. Most of mine are, but keep them in the shade.
I wouldn't worry about it at all