Non-synthetic biodiesel, which is what normally goes under the name biodiesel, is produced from bio-oil, which when mixed with alcohol undergoes a chemical reaction forming diesel and glycerol.

Biodiesel is produced from vegetable or plant oil or from animal or fish fat. The non-synthetic biodiesel is produced through a transesterification process, blending bio-oil with 10 – 20 % methanol (ethanol also may be used but the process is more complicated). The chemical reaction transforms the bio-oil and the methanol into methyl ester. The catalyst for the reaction is potassium hydroxide or another strong base such as sodium hydroxide.

Biodiesel is chemically different from petro diesel and “Green” or “renewable” diesel since it contains oxygen atoms.

If biodiesel shall be used (more than 5% biodiesel content) in vehicles not originally configured for this, gaskets, hoses and other rubber components needs to be replaced with biodiesel resistant components to avoid engine damage. Other considerations to be made when changing from regular diesel to biodiesel, is possible blocking of filters and strainers due to the alkalic properties of the biodiesel. In cold climates precausions (blending regular diesel or paraffin) also have to be considered to avoid blocking the fuel lines due to waxing.