A well done crumb coat can change the final look of a decorated cake, bringing its overall effect from “neat” to “WOW!”
So, what is a crumb coat?
A crumb coat is the base coat of icing on a cake. It is also referred to as "dirty icing" a cake. Generally there are at least two layers of buttercream icing spread on a cake: the first is the crumb coat, which seals in the crumbs.
The crumb coat makes sure no cake crumbs get into the second layer of icing, which would make your cake look dirty or rough.
Once the crumb coat is in place, you can then add an additional second coat to give it a nice uniform look, without worrying about stray crumbs. When you're learning how to properly ice a cake, the crumb coat is the first place that you start.
Now let's begin! Here's how to crumb coat a cake.
- Your cake (it should be well chilled)
- A leveler or a long serrated knife
- Offset spatula
- Bench scraper or straight icing spatula
- Buttercream of your choice
- A clean, empty bowl or extra cake pan
Preparing your icing
Before you begin, make sure your icing is stiff. You should be able to scoop it up with your spatula and turn it upside down over the bowl without it falling or sliding back into the bowl. The icing should hold its shape perfectly.
Step 1: Level the cake
The first thing you need to do is level your cake. All cakes need to be level, or your cake will crack and not hold its shape.
For smaller cakes I use a leveler, which can be found at a craft store or here on Craftsy. If you don't have one, you can use a long serrated knife to very carefully cut the top off your cake.
Step 2: Stack the ;layers
Once you have topped all of your cakes, you are ready to start stacking!
Start by spreading a thin layer of icing on your cake board. This way your cake will stick to the bottom of your cake.
Place your first layer on the board. Then, spoon or pipe your buttercream (or other filling) in the middle. Spread the icing carefully using an offset icing spatula.
Always add more icing than you think you need. It's much easier and cleaner to remove icing then add it.
Once your icing is nice and flat, you can continue stacking your cake layers.
Once you get to the top layer, place the last cake layer on top upside-down, so that the bottom of the cake layer becomes the top of the cake. This will greatly reduce the amount of crumbs you encounter.
Step 3: Coat the top of the cake
One of my tricks to getting a really nice crumb coat is to have an extra, empty bowl nearby. Anytime I get crumbs on my spatula, I wipe the icing into my extra bowl. This makes sure that my real bowl full of buttercream is totally free of crumbs.
Start by smoothing a thin layer over the top of the cake.
Step 4: Coat the sides of the cake
If any buttercream from the layers overflowed, you can spread that over the sides of the cake.
Then, you can start adding additional icing to the sides of the cake. Always start with more than you need. Lift some of the icing from your bowl and spread it over the side of the cake. Hold your spatula at 90 degrees against the cake, and use your other hand to turn the turntable to apply the frosting evenly.
Note: If you find your cakes are sliding around and won’t stay stacked properly, stack them as best you can and then place them in the fridge to harden the buttercream. After about 20 minutes, they should stay put and you can continue crumb coating your cake.
Step 5: Smooth the crumb coating
Once you have a nice thick coat of icing, hold your bench scraper or flat icing spatula flat against the side of your cake. Then turn the turntable and the scraper to make a nice, smooth coat of icing.
Step 6: Smooth the top
After finishing the edges of the cake, you will have peaks on the top edges of the cake.
To get rid of these peaks, move your offset spatula in a swiping motion, pulling the buttercream from the outer edge toward the center of the cake.
You now have a nice crumb coat! What next?
Whether you plan to decorate with buttercream or fondant, a second coat of icing can make a huge difference.
This second coat doesn’t need to be thick, it just needs to even out the blemishes that are always part of a cake.
Start by refrigerating your crumb coated cake. You want it nice and chilled. Leave it in the fridge for atleast 20-30 minutes to get the buttercream nice and firm. This helps the cake hold its shape when adding the second layer of buttercream.
Once your cake is chilled, pull it out and cover it with buttercream, using the same frosting method described above. Cover it evenly with buttercream using the offset spatula and then use the bench scraper to smooth the edges.
Place it in the fridge to chill. I always let mine chill for about 20 minutes so that the buttercream hardens. Then I wrap it in at least two layers of plastic wrap and place it back in the fridge to chill completely overnight, before covering it with fondant or adding other decorations.
Did you know Craftsy's YouTube Channel is full of free, quick video tutorials?
Check out this one on how to frost a cake four ways from cake designer and instructor Joshua John Russell.
See more on Craftsy's YouTube Cake Decorating Channel.