What is soapstock?

Soapstock is a byproduct generated during the production of biodiesel from oils or fats through a process called transesterification. It consists mainly of glycerin, unreacted oils, and various impurities, including soaps formed during the reaction. Soapstock can be further processed for the recovery of valuable components or used as a feedstock in animal feed, or for other industrial applications. Its management and utilization are important for the overall sustainability of biodiesel production.