Abstract: An improved biodiesel fuel preparation process using the step of simultaneous separation of biodiesel reaction product and glycerin, by specific gravity separation taking advantage of the pressure created by the heavier glycerin by using density loops, drawing of by-product glycerin from the bottom of the container while drawing off the lighter biodiesel reaction product from the top of the container as it is forced out by the density loop pressure. All of this is without the use of any pumps thereby reducing energy consumption and cost. Process efficiency is achieved by separating the methanolysis into two steps.