A type of rice used for risotto. When purchasing risotto it is important to know the variety and grade of the rice. The three main varieties are: Arborio, Vialone Nano and Carnaroli. The Arborio variety is a large plump kernel and the best choice for firm risotto. Vialone Nano is a stubby, small grain and your choice for wavy risotto. Carnaroli is a new cross-bred kernel and cooks firm. The four grades of rice based on size, color and consistency are: comune, semi-fino, fino and superfino. The comune is the lesser quality and superfino  the best.