Abstract: An anaerobic, pasteurizing conditioning system for treating matter such as whole and ground grain, minerals and other ingredients to increase the rate of their conversion and absorption during digestion and thus the nutritional value thereof. The system comprises a direct fired steam generator adapted for producing an effluent stream comprising steam and non-condensible gases, a vapor homogenizer for producing a substantially water-free treatment fluid from the effluent stream, and the treatment fluid containing insufficient oxygen for aerobic bacterial life. The treatment fluid, comprising steam and oxygen deficient non-condensible gases is discharged into the vessel for counter-current flow relative to grain passing therethrough.