Shea butter comes from the seeds of the African shea tree. Although it's primarily used in cosmetics for its healing and moisturizing benefits, the butter is edible and used often in African cooking. You'll find shea butter in both refined and unrefined forms. Refined shea butter goes through more processing and chemical treatment than raw or unrefined versions.
Unrefined Shea Butter
Unrefined shea is usually removed from the seeds by hand using a time-consuming process. Workers gather the seeds, which are about the size of a walnut, then boil them -- making the shells easier to remove. The boiled seeds dry and then pounded to break open the shells. Any bits of broken shell are removed so that the inner seed can be beaten along with water and then boiled to extract the fat. As the fat cools, it's whipped to make a smooth, usable product. If you purchase raw shea butter, it's unrefined and unfiltered, so flecks of impurities may remain as raw shea butter isn't usually passed through cheesecloth or commercial strainers. Unrefined shea butter may be filtered through cheesecloth, or another means, as long as the quality of the butter isn't affected.
Refined Shea Butter
Manufacturers process refined shea butter in large plants using chemicals, such as hexane. These chemicals help break open the seeds and speed the process of separating the fat, or butter, from the whole of the nut. They also remove any odor and make it smooth. The beneficial properties of the butter change during processing, and perfumes and preservatives are often added.
Benefits of Shea Butter
Unrefined shea butter acts as a barrier against moisture loss, making it invaluable in cosmetics and soap. It also has anti-inflammatory properties that support skin cells and protects against infection and irritation. The processing involved to refine shea butter may compromise these beneficial properties; added chemicals and fragrance increase the chance of allergies or irritation. Commercially refined shea butter may also contain fillers, such as other inferior oils.
Unrefined shea has a beige or yellow tinge but is never purely white. Lack of color is an indication the butter has been refined.
Storage and Expiration
The fatty acids in shea butter can turn rancid if stored too long or at improper temperatures -- such as in a hot truck. Use it within 18 months of extraction, suggests the American Shea Butter Institute, a quality-control organization. Refining shea can mask signs of impurity, such as an off-odor or color.