A) To see if your biodiesel needs purification - get half a bottle of biodiesel; top it up with water give it a shake and leave it 5 minutes to settle - clean water means clean biodiesel, soapy water means soapy biodiesel

1) Making Biodiesel is a chemical reaction with two phases - making the Biodiesel is called transesterification and the purification phase is where the biodiesel is cleaned up and made suitable for use.

2) When purifying biodiesel a dry wash is the best way to go because the industry standards want less than 500 ppm of water in the biodiesel so wet washing is no good.

3) Be careful not to use hydrogenated vegetable oils or semi solid fats as they will settle out of finished biodiesel when it cools and that can cause problems with your engine.

4) Using a final polishing rig is the best way for Ion Resin users and Wet Washers to achieve better biodiesel

5) Filtering down to 5 microns after making a batch is no good - the holes in some fuel injectors are 4 microns for a start

6) Don't use Palm Oil in the UK - its a tropical crop which solidifies in cooler climates and the UK is too far north to get the best of it. Rape oil is the best feedstock

7) Start on a low blend of biodiesel and increase your ratio slowly, and then after 1000 miles or so change your fuel filter because biodiesel cleans your engine and all the residual build up caused by carbon and hydrocarbon oil will migrate into your filters.