Abstract: In the continuous manufacture of cellulose pulp it has been found that air often remains in the lignocellulosic material subsequent to steaming the same. These air inclusions cause the lignocellulosic material to float in the cooking liquid, which results in interruptions in the digestion process. This problem is solved by means of the present invention, which relates to a method in which prior to being steamed, the lignocellulosic material is brought into contact with a heating medium. The method is characterized by supplying the heating medium to the advancing lignocellulosic material at several occasions; by distributing the heating medium in a manner such as to increase the temperature of the material in the direction in which it is advanced; and by separating condensed liquid from the lignocellulosic material.The invention also relates to apparatus for carrying out the above method.