After about 20 seconds, a valve opens to let the grain escape as expanded balls with the hulls removed. Under the high pressure, moisture is forced into the kernels, which, when released into the air, swell to several times their original size. The product resembles puffed breakfast cereals. Extruded grain is produced by a machine which applies heat and pressure by means of friction as the grain passes through a tapered screw. Various factors, including moisture of the grain, influence the character of the final product.
Grain is passed through a roaster of the type used for soybeans.
The grain is heated to about 300 degrees Fahrenheit and has a roasted odor with an oily, puffed and slightly caramelized appearance. Choice of Processing Technique Choice of processing technique is highly dependent on the cereal grain to be fed. A given processing technique may be very desirable for one grain, but quite detrimental to another. Corn may be fed without any processing, but not milo. Pressure treating appears to be desirable for milo, but harmful to wheat.