158 THE WHEAT INDUSTRY 



product he must start with clean grain. The 

 first step, therefore, is to separate the wheat from 

 husks, dirt, weed seed, and other undesirable 

 matter. This separating is accomplished by 

 screening processes. After screening, the grain 

 goes through scouring machines, where wheat 

 hairs, loose particles of bran, and any foreign 

 matter which may be clinging to the kernels is 

 removed. Some millers even wash the wheat 

 during the scouring process. 



Tempering the Grain. The grain thus purified 

 and cleaned must go through a tempering process. 

 The purpose of tempering is to put the grain in 

 the best possible condition for milling. Just what 

 this condition is depends upon the product desired 

 and the details of the milling method used. Heat 

 and moisture are always applied in some form. 

 Tempering toughens the grain and so conditions 

 it that, in grinding, the bran will remain in large 

 pieces and the various parts of the interior will 

 break up in such a way as the miller may desire. 



The Reduction Process. - - After the tempering 

 process the wheat is then passed through six or 

 seven sets of steel rollers, the first sets of which 

 are corrugated. Each passage through a set of 

 rollers is called a break. The rollers must be kept 

 cool since, if the flour is heated during the process 

 of reduction, it becomes dark. After each break 

 the product is sifted through silk screens. The 



