Steel-ground cornmeal, which is most commonly found on American shelves, is processed to remove the husk and germ of the maize kernel and stays fresh for as long as you need it if kept in a tightly sealed or air-tight container out of direct sunlight.

Stone- or water-ground cornmeal -- which is processed using millstones -- retains some of the husk and germ, making it more nutritious and also more perishable. Keep stone-ground cornmeal in the refrigerator to prevent its natural oils from going rancid; it will last up to 4 months.