In the United States, food regulations require that all peanut butters contain a minimum of 90% peanuts. Ingredients such as salt or sugar are allowed to be used as flavoring. Vegetable oils are also used in small amounts as stabilizers. Stabilizers are used to maintain the consistency of the peanut butter by preventing the natural peanut oils from separating from the product and rising to the top of the jar.
"Natural" or "Traditional-Style" peanut butters differ primarily because they do not contain a stabilizer. Consequently, the peanut oil may separate from the peanut butter and collect at the top of the jar. To prevent this, consumers often refrigerate these types of peanut butter. Although this keeps the oil from separating, the peanut butter will have a firmer, harder-to-spread consistency.