A method is disclosed for obtaining an alkyl ester fuel, i.e., a biodiesel, and alcohol from a feedstock mixture of free fatty acids and/or glycerides mixed with a simple alcohol, such as methanol. The method uses an electrostatic probe to provide an electrical field within the reactor. This causes the glycerin molecules to precipitate out of the feedstock mixture. A drain is provided in the reactor, to drain the glycerin from the reactor. When the precipitated glycerin reaches a level to make contact with the electrostatic probe, an electrical circuit is closed, which causes the drain to open. When the level drops, the drain closes. Glycerin absorbs water and draining glycerin from the reactor naturally dehydrates the fuel.