A hydraulically powered separator includes a separation chamber, an auger, a restrictor ring mounted at an output end of the chamber, a hydraulic cylinder having a reciprocating ram, a proportional hydraulic valve operatively coupled to the hydraulic cylinder, and a controller operatively coupled to the proportional hydraulic valve so as to control the hydraulic cylinder in a closed-loop manner. The chamber receives and processes a food product and has a cylindrical screen including a plurality of apertures. The auger is rotatably disposed within the chamber and an annular space and a volume is defined between the auger and the screen. The restrictor ring can be linearly and reciprocally displaced. Linear displacement of the restrictor ring varies a size of the volume. Movement of the ram causes pivoting movement of the restrictor ring to reduce or increase the size of the volume.