When having an indoor reception wedding cake frosting normally stays intact as long as the air conditioner is on. Many couples choose to have outdoor receptions at the beach, lake, park, gardens or even a backyard. The wedding cake is a main point of attraction for the guests. The last thing the baker or the bride wants is a melting pile of gooey frosting around the cake. Buttercream frosting holds up better than other frostings in hot humid weather, however there are still precautions to take to stop buttercream wedding cake frosting from melting.
Prepare buttercream decorations, such as roses ahead of time and store them in the freezer.
Add cornstarch to the buttercream recipe. Cornstarch helps stabilise the frosting and prevents it from melting as fast. Wilton offers a high humidity buttercream frosting recipe.
Use a good quality shortening in place of the butter in the recipe. Shortening holds up longer than butter in hot humid weather. Some people don't like the taste of frosting made with only shortening, so for an improved taste only replace half of the butter with shortening. Beware that any amount of butter will cause the frosting to melt at a faster rate.
Make the frosting as thick as possible by using less liquid than the recipe calls for. A thinner consistency frosting melts a lot faster than its thicker counterpart.
Use buttercream or fruit fillings. Creams and custard fillings may cause the cake layers to slide.
Store the cake in a freezer or in a cold place for as long as possible, prior to setting it up. If the cake is being displayed outdoors, it should be set up for display as close to the reception time as possible.
Transport the cake in an air-conditioned vehicle. If possible keep it in the direct flow of the air. Don't place it on the floor or in the boot.
Display the wedding cake in a shady area. Keep it out of direct sunlight. The cake should be displayed where the guests can view it, but it should be out of the main traffic area. If electricity is available, place a fan somewhere near the wedding cake to keep air circulating around it.