Abstract: Dough is moved by a screw conveyor (28) in the bottom of a hopper (12) through a hopper discharge opening (25) and through a discharge conduit (14). A wedge-shaped shield (58) is mounted in the lower portion of the hopper over the screw conveyor (28) and divides the dough moving down the hopper and guides the dough to opposite side of the screw conveyor and maintains an air passage (92) in the dough over the screw conveyor and in communication with the discharge conduit (14). A partial vacuum is drawn in the air passage (92) to evacuate gas from the dough.