Here's Why You Should Always Apply a Crumb Coat Before Frosting a Cake

A fudgy devil's food cake or fluffy vanilla cake must taste good, but you want it to look good, too. What can you do to achieve a professional-looking finish when frosting a cake? There's one additional step that you should always take: applying a crumb coat. While it will only require a few extra minutes of hands-on time, any pro baker will tell you that it's well worth the effort. But what exactly is a crumb coat? It's a thin layer of frosting applied to the top and sides of a cake before it's decorated with buttercream and edible garnishes.

"A crumb coat makes all of the crumbs stick together so that they don't get into your frosting or buttercream. Applying a smooth layer of buttercream seals the cake and prevents additional crumbs from getting into the outer layer of your frosting," says Melissa Weller, author of A Good Bake: The Art and Science of Making Perfect Pastries, Cakes, Cookies, Pies, and Breads at Home ($22.09, amazon.com). Bonus: The fat from the buttercream also provides an extra layer of moisture, which helps to prevent a cake from drying out. Ahead, we explain exactly how to apply a crumb coat and share those times when this step may not be necessary.

How to Apply a Crumb Coat

Before placing an unfrosted layer of cake on a turntable or cake stand, secure it with a dab of frosting on the bottom of the plate; this acts as a glue and will prevent the cake from shifting on the stand. Brush off any loose crumbs off the side of the cake and the turntable using a dry pastry brush. Use the same buttercream or frosting you will use to frost the cake for the crumb coat. To apply the crumb coat, all you need to do is spread a thin layer of frosting over the naked cake using a large offset spatula ($9.99, amazon.com) or pipe it on with a large pastry tip. If needed, you can use an angled bench scraper ($9.30, amazon.com) to remove any excess frosting and smooth the exterior of the cake. Weller says that you only need to use about one cup of frosting or buttercream for a crumb coat for a standard two-layer cake. Rather than keeping all the frosting in one mixing bowl, put the frosting for your crumb coat in a separate bowl. This will prevent any flyaway crumbs from getting mixed into the decorative frosting.

Once you've applied the crumb coat, place the entire cake in the refrigerator. "You're just chilling the frosting on the outside because you don't want to the crumb coat to move around when you apply more frosting. It should only take about 20 to 30 minutes to set up in the refrigerator," says Weller. Chilling the cake not only helps to set the crumb coat, but it also makes the interior super staple so that you don't have to worry about the cake layers shifting, says Penny Stankiewicz, chef-instructor of Pastry Baking Arts at the Institute of Culinary Education. Stankiewicz prefers placing her cake in the freezer for 10 to 15 minutes to save time.

When Not to Use a Crumb Coat

If you're making a cake that calls for a thin icing or glaze, there's no need to apply a crumb coat. Allow a pretty lemon glaze, such as the one used for this Lemon-Glazed Sheet Cake, to soak into the cake and set up on top before garnishing. An iced pound cake is another example of when you don't need a crumb coat.