If I want to fill a cake with chocolate ganache, does it have to be refrigerated? I'm making a cake on Fri or Sat afternoon. Is the ganache going to bulge int he layers? TIA

Most people feel that ganache (a traditional recipe, meaning not low fat or sugar) can be left out for 2 -3 days. I still pipe a dam of buttercream around the edge though.

It depends on the weather. If it is very hot in the room, the ganache will stay very soft.