Last week I started the Wilton 1 class at Michaels and this weekend I was SO excited to get started. I have been asked to have a cake iced for class this Thursday, but really thought I would start early and practice with a couple of cakes this weekend. I baked a 8 inch round SuperMoist Betty Crocker cake with nothing added to the recipe. I cooled the cake as my manual says and made the standard Wilton buttercream icing & tried to remove as many crumbs as I could. I tinted it light green as I was hoping to do some flowers on the cake. The cake was beautiful until I started icing it. 
Two spatulas into icing the cake I had crumbs EVERYWHERE! It looks like a mint chocolate chip cake at this point because of all the brown crumbs in the icing. 
The more I tried to keep it from happening... the more it did.
Any tips on how to avoid this silly mistake? I'm so frustrated!
Well now I've search around a little bit and I realize what I was missing is a crumb coat. Shoot! Why didn't my teacher mention this? I've thrown out 2 cakes because of this issue! 
Any suggestions on crumb coats would be much appreciated! Back to the drawing board!
I personally refrigerate my cake for a while to make sure it is cool. I always do a "crumb coat" first, which is a thinner layer of BC icing, which I always end up having a bunch of crumbs in. Once that is "crusted" or dried, then I do my top coat of BC icing, the one that will look pretty because all the crumbs are "trapped" in the crumb coat layer.
I wasn't sure if you already knew about doing a crumb coat or not - I never took the Wilton class, I wasn't sure what they taught!
One other thing is to make the sure that your BC is thin...not thick. If the icing is "picking up the cake" with it as you spread it on, its too thick. Add water (very small amounts at a time, like 1/8 tsp) until you're happy with the consistency. The only downside is that it'll take longer to crust and thus smoothen out, but its just a million times easier and even eliminates crumb coating if you layer it on thick enough.
Back in the dark ages, when I took Wilton course 1, the course manual had a recipe for an icing/filling, that was basically the class buttercream with corn syrup added to thin it. To this day, that is still what I use to ice white cakes. (I use half butter, half Crisco for other colors, but still use the corn syrup.)
As long as my icing isn't too thick, and I use the corn syrup, I almost never have to crumb coat. The exception is when I have a cake that for some reason wants to explode into crumbs when I so much as look at it.
I don't have the manual with me, so I can't tell you the amount of corn syrup that should be added. (I did notice that my son's manual from last year didn't seem to have this recipe.)
RedPanda
I didn't ever have the Wilton course I, but I do have quite a few old Wilton Yearbooks that actually say to add the corn syrup to thin for icing cake smooth. For one batch (1 lb of powdered sugar) it says 3-4 Tbsp(4 Tbsp is 1/4 cup), but I always make enough to use a whole 2 lb bag of powdered sugar and I don't measure the corn syrup - I don't add as much as the Wilton book says to (1/2 cup for the size recipe I make).
Don't throw out those cakes, make cake balls! My family loves them. They like the Cookies and Cream Cake Balls better than they did the Cookies and Cream Cake itself.
darkchocolate
Two options....
Thinly ice your cake and let it set. This is your crumb coat that you can later go and ice over.
Use the icing tip. I don't try and endorse much as a teacher, but I do LOVE the icing tip. I never crumb coat because of it and it saves so much time.
Also, your spatula should never be touching the cake at any time...just the icing. If you don't have an icing tip, squeeze all the icing on your cake in zig zags and then use a large spatula to ice your cake, so that you don't go back and forth between your cake and the icing bowl.
Hope that helped.
Good luck to you!
angie
When I took the Wilton I class my instructor told me three things:
1.Let the cake cool totally
2. Use the icing tip since is the best tip for icing
3. Smooth everything out with a spatula after the icing has a chance to set
As long as I follow those I haven't had any problems.
afort, my instructor didn't teach us to crumb coat either, so don't feel bad. It's probably because she's been decorating for years and never does herself. Personally, I love the icer tip. I don't crumb coat either and that tip saves so much time! 
My instructor didn't tell me to crumb coat either and I don't. But I also don't try to brush off the crumbs, that seems to make them multiply like bunnies! I did have a choco cake that had terrible crumbs and I just thinned and then melted the icing inthe micro. I then poured it over the top and spread it. I wasn't worried about ti being crumb free because I knew I could let it set and then refrost with the real frosting.
Maybe your frosting didn't crust because it was too thin. Next time try zapping it for a few seconds at a time until it is real thin! Good luck and enjoy the course!
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