How to Crumb Coat a Cake for Beginners

Hoping to learn how to crumb coat a cake? You've come to the right place! In our beginner's guide, we'll cover everything from how to create a crumb coating with buttercream or ganache, how thick the coating should be, to chill or not to chill, and more.

If you are asking yourself "what is a crumb coat", let us explain! When you bake a sponge cake and are preparing to decorate it, little pieces of sponge commonly crumble off the sides of the cake. While this isn't a disaster, those crumbs can end up getting in the way when decorating. Especially if you're covering your cake with buttercream or ganache, those crumbs can get trapped in what you want to be a nice smooth finish!

A crumb coat is a very thin layer of frosting or ganache, applied all around the sponge, to seal in those crumbs before decorating. It's easy to do and a really useful step to take in elevating your cakes.

Contents How to crumb coat a cake with buttercream Can you crumb coat a cake with ganache? How thick should a crumb coat be? Do I need to chill the cake before crumb coating? How long should a crumb coat set before frosting?

How to crumb coat a cake with buttercream

We asked one of our amazing cake pro friends, Zara (@bubbasbakes) to show us how to crumb coat a cake with buttercream, and she delivered!

To crumb coat a two layer sponge cake, begin by piping a buttercream border around the top of one of your sponges. Fill in the circle with more buttercream to create your filling between the layers. Then place the second sponge on top.

To create the crumb coating, use a palette knife to spread a thin but even layer of buttercream around the entire outside of the cake. Keep going over it till it is completely coated and smoothed down. Most professional cake artists will apply two coats, maybe three, to ensure all crumbs are totally sealed in!

Then, if you're stacking a cake with more layers, continue adding filling, the next sponge layer and repeating the process with your buttercream!

Buttercream is perfect for crumb-coating a celebration cake that will only be on display for a couple of hours. For a wedding cake that has to last all day, use ganache.

What buttercream is best for crumb coating?

American buttercream is a great all-rounder and a good option for creating a crumb coat for your cake. So don't worry about working with anything fancier! Check out our guide on how to make American buttercream here.

However, your best bet is to use the same buttercream as you are using for your final layer! So, if you're covering your cake with Swiss Meringue buttercream, use this to make your crumb coat too. Not only does it save you from having to make up extra ingredients, but it just keeps everything nice and consistent texture and flavour wise.

What tools do I need to crumb coat a cake?

Thankfully, you don't need too many tools for crumb coating! The main things you'll need to have to hand are a spatula to apply the buttercream and a scraper to remove any excess. We recommend an angled spatula or palette knife, for ease of application.

To make your life a little bit easier, however, a turntable is very handy! By having your cake on the turntable you can work more quickly and don't have to move around the cake yourself.

And, not specifically for the crumb coat, but keep in mind you will need a cake leveller or sharp knife to trim off any excess sponge or a domed top.

Can you crumb coat a cake with ganache?

Yes, you can use Ganache for crumb coating a cake. It's a popular alternative to buttercream and a great option for a really stable coating. It's also the best option for using underneath fondant/sugarpaste icing.

Ganache is perfect for crumb-coating wedding cakes, which have to last on display for up to seven hours! Zara told us she keeps her cakes refrigerated right up until she leaves for the venue, meaning they'll naturally come to room temperature once set up, and stand tall and strong all day.

Just follow the same steps as you would for buttercream, using the same tools, for a perfect ganache crumb coating.

How thick should a crumb coat be?

A crumb coat is a very thin coating of buttercream or ganache - you should still be able to see the sponge through it! It's really just a sealing layer. There's no set number of millimetres, but a general rule of thumb is to aim for 3-4mm.

How many layers of crumb coat should I apply

The number of layers is entirely up to you, but the main objective is to have the outside of your sponge free from any crumbling. If you are confident you've achieved that in just one thin layer, hooray! No need to go on.

However, most professional cake artists will apply two layers (sometimes three!) of a crumb coating to ensure it does the job.

Do I need to chill the cake before crumb coating?

Chilling the cake before applying your crumb coat can help to improve the results. Because when the sponge is cool it is less likely to crumble, applying your layer(s) of buttercream or ganache when it has been chilled can help seal everything in properly.

Naturally, if your cake is warm the crumb coat is going to melt! So, the most important thing is not to try to crumb coat your cake fresh out of the oven. Let it fully cool to room temperature at least if you aren't planning to refrigerate or freeze it first.

How long should a crumb coat set before decorating?

It can take anywhere between 30mins (in the fridge) to overnight (8hours) for a crumb coat to fully set. However, you can save time here by working with frozen sponges!

We asked Zara (@bubbasbakes) for her advice!

"I personally work with frozen sponges, baked freshly the day before and frozen overnight to not only lock in the moisture, but also to help with speeding up the processes which is vital when I have 3 wedding cakes on the go.

I fill, stack and crumb coat all in one and because my sponges are cold, the crumb sets super quick meaning by the time I have filled, stacked and crumb coated all three tiers, I can go back to the first one I worked on and add the structure and final coat."

Ready to crumb coat like a pro? Share your bakes with us on Instagram, TikTok and Facebook – we can't wait to see them. And follow our accounts for daily cakey inspo, tips and tricks.

Looking for more cake decorating tips and advice?

How to Make American Buttercream – Our Complete Guide

The Ultimate Guide to Food Colourings for Cake Decorating

What’s the Difference Between Sugarpaste, Modelling Paste & Flower Paste?