Processes for the synthesis of high purity fatty acid lower alkyl esters comprise the steps of: (a) converting a fatty acid source to a product mixture comprising lower alkyl esters and by-products; (b) water-washing the product mixture at elevated temperature and elevated pressure to remove by-products; and (c) fractionally distilling the water-washed product mixture to obtain high purity fatty acid lower alkyl esters. At least a portion of the fatty acids have from about 20 to about 24 carbon atoms. The high purity lower alkyl esters have an acid value no greater than about 1.0.