Workers in the mid west have developed a catalytic route to biodiesel with few or no by products... The downside is that you need to be able to heat the catalyst to 300C at a pressure of around 2500 psi, so its not likely to be a process for home brewers,and you need a sulphonated zirconium, alumina and titania oxides. The process, called Mcgyan, is named after the three inventors. The single pass conversion factors look pretty impressive at between 90 and 98%. You can check out the full explanation in a Continuous Catalytic System for Biodiesel Production on Science Direct.
Hattip to Gas2.0
Hattip to Gas2.0