Yesterday I made syrup from sugar purchased from Aldi. When I was heating it, it turned all white and foamy, and I had a devil of a time keeping it from boiling over. When it cooled, there was a white scum (?) on top. I usually buy a store brand, and as soon as it boils, it turns clear. It boils smoothly and there is no residue on top. Has anyone else experienced this? Is it "cheap" sugar from Aldi? Is there any reason to NOT feed it to the bees?