Cornmeal by definition is dried corn kernels that have been ground in one of three textures – fine, medium, or coarse. It is a popular dry corn because of its long shelf life, freedom from black specks, and bright colour. There are two methods of grinding. The old-fashioned water-ground (also called stone-ground) method – so named because water power is used to turn the mill wheels – retains some of the hull and germ of the corn. Because of the fat in the germ, water-ground cornmeal is more nutritious, but will not keep as long and should be stored (up to four months) in the refrigerator. The other method to grind the maize is performed by high speed, big volume steel cylinders or hammer mills. Cylinder mills grind grains with rigid or smooth pairs of cylinders that rotate at high speed. Grains are forced between the cylinders which grind and tear the kernels instantly.