Converting extracted oil from the seed is taken through several steps in order to achieve some products like biodiesel. Once you collect enough oil from your oil press machine, it requires the oil to be chemically processed to rid off other undesirable impurities. Usually, a catalyst is used to get rid of glycerin molecules before combining the alcohol content with fatty acids that goes to produce esters. The kind of alcohol used at this stage could be ethanol or methanol although methanol is usually the most preferred by individual mill owners. You should be cautious when using your oil extraction machine to produce esters. This is because the process involves use of flammable chemicals. Ensure you follow due procedure as indicated by your vendor instructions.