Knowing all of the facts about fillings, which ones need to be refrigerated and which can be left out at room temperature is very important for a cake decorator selling their cakes or a home baker preparing desserts for friends and family. Cake fillings will determine your reputation and I’m sure that you certainly do not want to make anyone sick.
We know that butter cream frosting does not hold up well in the heat. Think about a fondant covered cake with a filling. Do you think it's safe to be out in the heat? Maybe not. Chocolate ganache filling melts if left in the heat for a period of time. Did you know that? It's deceiving. It sets firmly so you can use it as a filling in sculpted cakes and are able to shape it into truffles that are delicious to eat but when a ganache filled cake sits out in the heat, the ganache gets soft and starts to disintegrate which, if it is a stacked cake, could come tumbling down.
Do some advance planning. Make sure that your clients or hosts are educated about the types of fillings that would be best suited for their events.
Fillings can be made from scratch or bought. The fillings made from scratch are highly perishable and should remain refrigerated. New filling recipes should not be tried the night before an event. If you have to do something new, test the recipe out two weeks before. That way, if you need to make changes, you have time to do it or get help.
Fillings that come in sleeves at your local cake store can be used right out of the sleeve as they are and the remainder can be refrigerated up to 6 months.
If you decide to use fresh fruit in your filling, please make sure to use the freshest fruit you can find and prepare it as close to serving time as possible. If you must put the cake together the night before (for example, strawberry cake with fresh strawberries in the middle, cut the fruit in half. Smaller pieces will get mushy overnight and not make a good presentation.
Not sure how to properly whip the cream for your filling, use the aerosol can version, sprinkle with confectioner's sugar and add your fresh fruit and cover with more canned whip cream and more confectioner's sugar.
If your cake has a fresh fruit filling and the cake is covered in fondant, stack the cakes at your venue. The fondant will get gummy if you stack them sooner.
If your event is held indoors whether it is a big hall or someone's home, feel free to use a filling that has to be refrigerated. Cream cheese, custards, pastry cream, whipped cream, puddings, and any mousse type fillings that include fresh fruit are perfect for these venues. Cakes can remain refrigerated until right before serving. Let people know when they request these fillings that there needs to be space in the refrigerator to store the cake until serving. A lot of people fill the refrigerators with everything else and then have to scramble to find room for the cake. It cannot sit out for a long period of time or there will be a disaster.
Speaking of disaster, please do not mix up a batch of the pudding mix as it is instructed on the box and use that as a filling for your cakes. Unless it's made like a mousse, it will not hold up to the weight of the cake on top and will ooze out and make a mess.
When in doubt, make a test cake to see what happens when you refrigerate your cake with the intended filling and frosting/fondant. You don't want to be surprised about this.
Refrigerated fillings are delicious, though sometime they are a double-edged sword. Butter cakes do not taste their best right out of the refrigerator. Combine them with a refrigerated filling, and you have to make a choice. Cold cake or warm filling. Either one is not good. And, you don't want people telling the host/hostess that the cake was "dry" because it was cold. Switch to a different cake recipe or use sugar syrup on your cake layers before assembling to help the cake retain moisture so it doesn't dry out while in the refrigerator.
Remember that gum paste and royal icing decorations on a cake will be ruined if it is refrigerated.
Any of the sleeves of fillings bought at your local cake decorating store should be fine at room temperature. So are the jellies, preservatives and ganache. Whenever using the fillings in the sleeves, remember the dam of frosting around the edge of the cake. You don't want it oozing out once the cake settles. Trust me on this one. That is why it's best to use the following technique for fillings.
Make sure that you have a thick dam of frosting going around the edge of the cake. Add no higher than a 1/4" high layer of filling. For example, whenever I use lemon filling, I split the cake layer in half, add the dam of frosting, spread the lemon filling and then put the two layers together. Frosting goes between the cake layers so it will be:
Thin layer of frosting that covers entire cake:
Frosting dam - Lemon filling
Middle frosting layer
Frosting dam - Lemon filling
Always refrigerate to let the frosting set. Once it's set, cover the cake in fondant. Set your cake in a cake box that has room for it to fit without the fondant touching the top or sides of the box. Refrigerate again to set. This is your insurance policy when you deliver the cake. If the party is at your house, and it's cool inside, you can leave it out. Refrigerating this kind of cake makes it easier to slice so that the filling doesn't ooze out of every slice. You want a nice presentation.
When you cake is removed from the refrigerator, please remember to give it time to "sweat." Don't touch it during this period or you will leave a mark. Let the cake come to room temperature. Usually, by the time you travel to your destination, and it's time to serve the cake, the fondant will be okay to slice and the dewy, shiny look will be gone.
What Kind of Filling is It?
Lemon, chocolate, caramel, banana, apricot, chocolate chip, and some other fillings are easily recognized in a cake just by looking at them. Don't make your guests guess what they're eating. Make tent cards for each table that includes this information or add it to the menu card. With so many food allergies out there, you don't want to be remembered for making someone sick.
To Freeze or Not to Freeze
Never freeze a cake filled with a custard filling because it will separate. Whipped cream cakes have been frozen. It depends on the type of whipping cream used. Check the container to see if it tells you that it can be frozen because you do not want your cake to weep. Rose Berenbaum, in her book, The Cake Bible, shows you how to stabilize the whipping cream with gelatin.
Enjoy using your cake fillings to take your cakes to higher levels. Just be safe.
Debra J. Mosely