"The Foolproof Method has been used to make many thousands of gallons of high-quality biodiesel from all sorts of feedstock. Many individual biofuellers have adopted it as their standard method.
In two professional biodiesel fuel analyses, two years apart, home-brewed biodiesel made by this method met the German DIN 51606 biodiesel standards. This means the fuel is suitable for warranty repair by VW for all their vehicles made from 1996 till today. You can make DIN and ASTM-compliant fuel just by carefully following the instructions."