Rancilio ROCKY Doser Electric Burr Grinder - The Rancilio Rocky burr grinder uses slow turning commercial grade grinder burrs grinding wheels to cut the coffee bean into uniform coffee grounds. This is better than a standard blade grinder which usually does not produce uniform grind sizes. Consistent grind size is important to promote better taste and aroma. It is especially important if you are grinding coffee for an espresso machine which needs a fine and consistent grind.