Castor oil comes from castor beans and contains around 50-55% oil. This oil is high in ricinoleic acid at over 85% and has properties like a low melting point that make it suitable for industrial use like biodiesel production. Castor oil has a high cetane number, which is a measure of how well a fuel will burn in a diesel engine, ranging from 45-65 for most biofuels but higher for castor oil. It is also relatively inexpensive compared to other oils, making it cost effective for biodiesel production despite ongoing research into other variables.