patented a process for making soap from natural oils or fats. This two step process included making fatty acid esters from oils, then producing soap from the esters. The crude oil was first refined to remove a certain amount of water, free fatty acids mucilaginous matter, protein, coloring matter and sugars. The water content was less than 1% after refining. Although the author did not mention the contents of other impurities after refining, the normal refining process met the requirements of the transesterification process.