Disclosed is a jacketed, tiered baffle, bioreactor tank comprising an outer cylindrical-shaped jacket and a cylindrical tank having an inner tank surface defining a chamber configured for supporting a flexible bag disposed within the chamber, and an outer tank surface having tiered baffles configured for routing a heat exchange fluid around the entirety of the outer tank surface, the cylindrical tank disposed axially within the outer cylindrical-shaped jacket. The outer cylindrical-shaped jacket is sealed to the cylindrical tank in a manner sufficient to prevent or minimize loss of the heat exchange fluid.