This is the second time that I've made buttercream and though I cover it it gets gritty. What in the world would cause this?? I have to figure this out so that when I make my wedding cake this does NOT happen. Thanks guys!

Did you use the all crisco recipe? If so, is it possible that the crisco was bad. It can go bad very easily! Also, if you don't cream it well before you start slowly adding the powdered sugar, it can sometimes taste a little grainy.

Do you use popcorn salt in your buttercream? Some people say that if you don't dissolve the salt completely, your buttercream can be gritty as a result.

Did you use a generic brand powdered sugar?? The only time I had this happen to me was when I used the Target Brand sugar. I read somewhere on here that you have to use 100% pure cane sugar - otherwise your buttercream can become gritty. Now I only use C&H Sugar or the Safeway/Vons brand seems to be fine too.

Quality ingredients are important, as has already been posted, but also proportions and how you mix it.

If you would put your recipe here, you could get more specific advice.