I iced a cake in red buttercream icing. No different than I have done for the past 9 years. But there are tons of tiny dark spots all over the cake in the icing. What causes that?
My icing is sweetex, crisco, butter, flavoring and powdered sugar along with a few tbsps of coffee creamer to get it to the desired consistency.
Are you sure you mixed the coloring in good?
Old gel or a contaminated container or color gel? I don't know, just throwing that out there.
I can not answer your question about buttercream but I had the same thing happen when I added tysol to my fondant and did not mix the tysol totally before adding the coloring. I wonder if there may of been some dry sugar that had not been totally mixed yet. Maybe someone else has had this experince.