I made royal icing while I stayed with my parents in law in Australia for holiday. I felt the royal icing "grainy," which I haven't experienced at home in Japan. I used CSR pure icing sugar there. I wondered if it would be because I used different egg white powder, but after I read Julia's comment, I suppose it might be because of the powdered sugar. I've never thought about how fine powdered sugar is, because any powdered sugar in Japan I ever used has no problem!