I never sift!! Could simply be a bad batch of PS -- too much cornstarch.
Thanks for the input! I live in Olympia, Washington where it has been raining and humid for several weeks now, and some of my powdered sugar had been opened previously. If moisture is a cause for granulation, that very well could be the answer. I also used a tablespoon of lemon extract and a tablespoon of real lemon, but I have used lemon as a flavoring before. The cakes are for a preschool graduation, and supplied by "Free Cakes for Kids, South Sound", and I don't think the little ones will care, but I would not like to repeat this error. Still I like this recipe, and will try it again hoping that this was a one off. Thanks again, Sheila
For some time I have been reading that you should use the better brand of PS to prevent grittiness. I think it is using PS made with cane, not beets. Well one time I bought the good PS with cane and compared it to my usual made with beet sugar (if it is made with cane it says that on the package. If it says nothing then it is made with beets) that I had in the freezer. And it was less gritty. Not a big enough deal that I will completely switch but it did make a difference so this may be part of it.
I use indydebi's buttercream and usually don't have any problems with it ...however, this past weekend I made some and it was GRITTY. I used the same powdered sugar I usually do and I always sift. I don't know what happened either! Very strange!
Make sure you check your shortening. If there are no trans fats it can get gritty too and seep. The trans fats are the only emulsifiers you have in these buttercream recipes.