The apparatus operates with steam above atmospheric pressure. It includes a pressure vessel (40) with an interior (8), at least one movable container (4) holding oil palm fruit with open top exposed to the interior (8). A steam supply conduit supplying steam from an external steam source is connected to the interior (8)； the container (4) has a solid floor (11) with at least one open aperture (51) in fluid communication with the interior of the container (4). A channel (15) in fluid communication with the interior of the container (4) is in further fluid communication with another channel (16) which is in fluid communication with exterior of the pressure vessel (40). A method of introducing pressurised steam into the pressure vessel (40) and dispelling trapped air within the stack of oil palm fruit bunches (10) and condensate from the container (4) is disclosed.
