Burr mill

A burr mill or burr grinder is a mill to grind hard, small food products between two revolving abrasive surfaces separated by a distance usually set by the user. When the distance is larger, the resulting ground material is coarser. When the two surfaces are set closer together, the resulting ground material is finer and smaller. Often the device includes a revolving screw that pushes the food through. It may be powered electrically or manually.