Vegetable oils and fats are produced by chemical or mechanical extraction from plants. This produces a kind of oil that still has many unwanted substances, such as pigments and smell, which influence the quality of the refined product. In essence, the factors influenced are taste, shelf life, smell and color, as well as the ability to use the oil for further technical transformations. Depending on the process, between four and eight percent of usable vegetable oil is lost. There are two basic procedures to refine vegetable oil, chemical refining, and physical refining.