A peanut starts off growing as a flower and will eventually burrow into the ground where it matures. Each peanut shell contains two nuts--sometimes three or four--which are covered by a red or brown skin. Peanuts are available for purchase shelled, unshelled and in a nut butter form.

Shelled peanuts should be stored in airtight containers, ideally in a refrigerator or freezer in order to preserve freshness. They will remain fresh for three to six months.

Peanuts still in their shell need to be stored in a cool, dark place away from moisture. If stored in the refrigerator they will maintain their freshness for up to nine months.

Commercially manufactured peanut butter requires no refrigeration and can be stored for up to one year. Once the jar is opened, it can be stored for up to six months.

Natural peanut butter can be stored for up to one year on the shelf. Once opened, the jar will need to be stored in the refrigerator and will remain fresh for up to six months.

Homemade peanut butter needs to be sealed in an airtight container and stored in the refrigerator. It should be used within two weeks.