why is buttercream grainy when adding powdered sugar, ho long do ihave to beat it?!
Powdered sugar can create a grittiness to the buttercream depending on the coarseness of sugar itself. Most powdered sugars come in either 6x (standard) or 10x (finest ground). I get the smoothest results when I use 10x powdered sugar. The mixing time depends on what recipe you are using. Typically, the longer you beat buttercream the more lighter, whiter, and fluffier it becomes because you are beating air into the cream.
What revipe are you using? I have Never had powdered sugar leave a grainy texture. I am sorry to tell you this but you are doing something wrong.