coffee grinder

Burr grinder for poppy seeds, burr visible on front A burr mill, or burr grinder, is a mill used to grind hard, small food products between two revolving abrasive surfaces separated by a distance usually set by the user. When the two surfaces are set far apart, the resulting ground material is coarser, and 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.

Burr mills do not heat the ground product by friction as much as blade grinders ("choppers"), and produce particles of a uniform size determined by the separation between the grinding surfaces.