This simple staple, made from dried corn kernels that have been ground into meal, comes in a number of variations. The first, texture, depends on how well the corn kernels are ground; cornmeal can come in fine, medium, or coarse grind. The second, color, depends on the type of corn used; cornmeal can be yellow, white, or blue.
The last variation is the method of grinding: it can be traditional water-ground (also called stone-ground) or the more modern steel-ground. In water-ground cornmeal, water is used to power the rotation of the mill’s stone wheels. This method does not entirely eliminate the corn’s hull and germ; this makes water-ground cornmeal the more nutritious choice because it retains more fiber and other nutrients, but a higher fat content also means it will spoil faster than steel-ground. Water-ground cornmeal should be stored in the refrigerator for up to four months. Steel-ground cornmeal is ground on steel rollers that almost entirely eliminate the husk and germ; without the fat-containing germ, steel-ground cornmeal will keep almost indefinitely in an airtight container in a cool, dark place. Usually, water-ground or stone-ground cornmeal will be labeled as such; unlabeled cornmeal is typically steel-ground.