Abstract: An apparatus and method for treating oil-bearing material which includes an extruder having an elongated enclosure with an inlet end. The extruder also includes a worm assembly for working and advancing the material through the enclosure from the inlet end to the discharge end. A high pressure region is located adjacent the extruder inlet end. A force feeder provides material to the high pressure region at a specified supply rate. Oil in the material is liberated and drained in the high pressure region to a specified level prior to entry of the material into the extruder inlet end. The apparatus also includes an outlet in the high pressure region for drainage of the released oil, as well as a screen over the outlet to prevent material greater than a specified size from exiting the high pressure region through the outlet. The seed material is mechanically worked via the action of a rotating screw in the extruder. At the same time, steam is injected into the extruder to condition the worked seed material.