Peanut butter contain at least 90% peanuts; the remaining <10% usually consists of "...salt, a sweetener, and an emulsifier or hardened vegetable oil which prevents the peanut oil from separating". In the US, no product labelled as "peanut butter" can contain "artificial sweeteners, chemical preservatives, [or] natural or artificial coloring additives." Some brands of peanut butter are sold without emulsifiers that bind the peanut oils with the peanut paste, and so require stirring after separation. Most major brands of peanut butter add white sugar, but there are others that use dried cane syrup, agave syrup, or coconut palm sugar. Organic and artisanal
Vegetable oil fuel used may seem insignificant today, but such oils may perhaps become in course of time of the same importance as some natural mineral oils and the tar products are now." Periodic petroleum shortages spurred research into vegetable oil as a diesel substitute during the 1930s and 1940s, and again in the 1970s and early 1980s when straight vegetable oil enjoyed its highest level of scientific interest. The 1970s also saw the formation of the first commercial enterprise to allow consumers to run straight vegetable oil in their automobiles, Elsbett of Germany. In the 1990s Bougainville conflict, islanders cut off from