TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The feedstock comprises free fatty acid (greater than 5, preferably greater than 50, particularly greater than 95) wt.% or oil or restaurant trap grease. The first and second alcohol comprises at least one 1-4C alcohol (preferably methanol, ethanol, propanol or butanol). The acid catalyst comprises at least one catalyst selected from sulfuric acid, an alkyl or aryl sulfonic acid, a cation exchange resin or a fluorinated ionomer resin. Preferred Method: The mixture is reacted at 80-200 (preferably 80-150, especially 85) psi to prevent the mixture from boiling and at 80-150 (preferably 115-150, especially 115)degrees C. The separation step involves separating part or all of the water and glycerin that are formed as byproducts of the process; and removing part or all of the alcohol employed in the process. In step A a feed stock comprising free fatty acid and glyceride is contacted with alcohol and an acid catalyst at 80 to 130degrees C and greater than atmospheric pressure to form a reaction mixture, followed by removing water and glycerin from the reacted mixture to isolate a partially reacted feedstock (F1). The method further involves(A) isolating biodiesel from the composition by fractional distillation carried out at 1-10 (preferably 1.5) torr and collecting the distillate at 135-160degrees C;(B) contacting the composition of (I)/partially reacted feedstock (F1) with a second alcohol and a second acid catalyst to form a second mixture under similar conditions as the first mixture (preferably both first and second mixture are reacted at similar pressure and temperature) and isolating an alkyl ester of a free fatty acid from the reacted second mixture;(C) contacting the alkyl ester of a free fatty acid with another alcohol and another acid catalyst to form a different mixture;(D) reacting the different mixture at 80-200degrees C to form a different reacted mixture;(E) separating from the different reacted mixture the alkyl ester of a free fatty acid; and(F) repeating steps C through E to obtain a desired yield for the alkyl ester of a free fatty acid. EXAMPLE - No suitable example is given.