If you want to show off your cake decorating skills, pastry chefs recommend not refrigerating a fondant-covered creation. The fondant sweats when removed from the refrigerator, causing it to sag into a soft, sticky mess.
Keep It Safe
Fondant, a sugar confection, can be rolled out into a flat sheet to be placed on baked goods such as cakes and cupcakes, or poured onto the desserts. It adds a smooth, professional look to cakes and keeps the cake underneath moist. Although poured fondant that hasn’t been applied to a cake can be stored in the refrigerator for several weeks and then reheated into its pourable form, unused rolled fondant should be kept in an airtight container -- outside of the refrigerator -- where it will last for up to two months. Once fondant has been applied to a cake, it should be kept at room temperature for no more than three or four days.
Don't Sweat It
If you refrigerate fondant-covered pastries, when you remove them from the fridge, the fondant may sweat and begin to sag. Several factors can cause fondant that's out of the fridge to sweat, such as moisture from the cake and the fondant, plus the humidity in the atmosphere around the cake and the presence of undissolved sugar crystals. In cases where cream-filled baked goods are covered in fondant and refrigerated, the fondant can literally slide right off the pastry if jostled. Avoid refrigerating fondant-covered pastries to limit the amount of sweating.