Crude Glycerine (CG), also known as crude glycerol, is a byproduct obtained during the production of biodiesel or fatty acid derivatives. It is a viscous liquid composed primarily of glycerol, which is a colorless and odorless compound.

CG is produced when vegetable oils or animal fats undergo a process called transesterification, which converts them into biodiesel. During this process, the triglycerides present in the oils or fats are reacted with an alcohol, typically methanol, in the presence of a catalyst. The result is the production of biodiesel and a co-product known as crude glycerine.

Crude glycerine contains impurities such as methanol, catalyst residues, fatty acids, and soap. The exact composition of CG can vary depending on the feedstock used and the specific process employed in biodiesel production.