A vessel within which a controlled chemical or biochemical reaction takes place. They require a charge of reactants, which may be liquid or solid including the use of catalysts. The chemical reaction is allowed to proceed until a required concentration of product has been achieved. The reaction may require heating or cooling depending on the thermodynamics of the reaction. This can be achieved by the circulation of a heat transfer medium through a surrounding jacket or through internal coils and tubes. Once the reaction is complete, the reaction materials are recovered. This type of reactor is considered to be versatile since it can be used for many types of processes.