Parmesan is a dry, hard cheese made from skimmed or partially skimmed cow's milk. It has a pale-golden rind and a light-yellow interior. Sharp in flavor with a granular texture, this cheese is primarily used for grating.
To keep Parmesan fresh, proper storage is necessary: It should be wrapped tightly in plastic wrap and kept in the refrigerator. Cheese that has been exposed to air may start to turn white, or the rind may start to thicken. If this is the case with your Parmesan, a simple process can be used to revive the cheese, making it ready for your next recipe.
Soak a cheesecloth in water, then ring it out until it's just damp.Wrap the cheese in the damp cloth, then in a layer of plastic wrap. Place it in the refrigerator overnight. The next day when you remove the cloth, the cheese will be fresh again, and ready for use. Wrap it in a new piece of plastic wrap, and place it in the refrigerator.