From the title, you’d think that I was going to talk about covering something in crumbs. Actually, it’s the very opposite.
Crumb-coating is actually a technique used to help you get a nice smooth finish when you ice a cake with buttercream.
What you essentially do is to apply a very thin layer of icing all around the cake and let that dry. This thin layer seals in all the crumbs so they don’t appear in the next layer of icing, which should go on much smoother.
When you do a crumb coat, you want to push the buttercream icing quite firmly into the cake. The cake might tear a little but press on. (Got the pun?) Scrap off any excess buttercream, but don’t mix it back with the rest of your icing or you’ll contaminate it with crumbs. Your cake will look spotty and horrible, but don’t worry!
Put the cake in the refrigerator for about an hour. The icing should feel crusty and dry to the touch. Now, begin your second coat of icing. You should find that it goes on nice and smooth, and as long as you don’t actually rupture the crumb coat, you won’t have to worry about any crumbs in the top layer of icing.
Now, do you have to do a crumb coat? Not all the time. Crumb coats are useful under two conditions: (1) your cake is slightly over-baked and it’s gotten quite crumbly around the edges; and (2) the icing is a much lighter colour than your cake, so crumbs will definitely show up. Crumb coats can guarantee that you get a beautiful, crumb-free finish. The picture below shows the earlier crumb-coated cake with its final layer of icing. Not a crumb in sight!
However, I have to say that getting a few crumbs in your icing is not the end of the world. If that happens, just run with it! Sometimes, it might turn out to be a beautiful accident, like this red velvet cake with white buttercream icing that I made for my Mum for Mother’s Day.