Abstract: A new Indirectly Heated Screw Processor Apparatus and Methods wherein a series of rotating helical ducts or hollow flites radial to a shaft, transfers heat via a heat transfer medium, the first face flite disc facing in the opposite direction to material or product flow and thereby significantly increasing the product retention time and thermal heat transfer. Heat is transferred via a heat transfer medium through a rotary joint to the inner surface of the hollow shaft. The flites continuously traverse a longitudinal portion of the rotor wherein said flites are equally spaced apart in a substantially parallel angle and orientation, the spacing, or pitch, concluding in a non-flite, or “dead zone” region of the longitudinal length of rotor wherein the material or product accumulates and is retained for an increased amount of time, and when compared to conventional indirect-heating screw conveyors, the apparatus provides a higher percentage of flite height fill.