A method for extruding a comestible material comprises the steps of passing comestible material into an extruder (100) with rotation of the extruder screw(s) (120, 122) and delivery of fluid comprising steam and water into an opening (114a) of the extruder barrel (104). The fluid delivery step comprises separately directing individual quantities of steam and water into the casing (72) of a static mixing section (54), and blending the steam and water to create a blended mixture, and then delivering the blended mixture into the barrel (114a). The blended mixture is delivered to the barrel opening (114a) by a conveying assembly (84, 86) having a pipe assembly (86) with an outlet in communication with the barrel opening (114a); the pipe assembly (86) and opening (114a) have diameters less than maximum internal diameter of the static mixer casing (72).