116 FIELD CROP PRODUCTION 



be explained here in detail. The grains are run, first 

 between corrugated iron rollers, where they are cut and 

 broken, but not crushed. This is called the first break, 

 after which the wheat is sifted several times to separate a 

 part of the interior from the rest of the kernel. The scalp- 

 ings, as the bran and adhering portions of the interior part 

 of the grain are called, are then run through another set of 

 rollers, with finer corrugations, and again sifted. This 

 process is repeated imtil no more of the interior may be 

 separated. The interior of the grain thus removed is called 

 middlings. The middlings are run through the middlings 

 purifier. This removes the germ and small particles of 

 bran, after which the middlings are ground between 

 smooth rollers, sifted, and reground until they are of the 

 required fineness, which an expert is able to determine by 

 the feel and color of the flour. 



103. Grades and kinds of flour. — Many different grades 

 of flour result from the modern processes of milling, based 

 upon the purity of the product, that is, freedom from germ 

 and bran particles. The finest flour is the patent grade, 

 which may be further graded into first and second patent, 

 while the lowest grade is known as red dog. In all of the 

 large mills, and in many of the smaller ones, great care is 

 taken to maintain uniform quality in the flour. For this 

 purpose an expert is employed to make actual baking tests 

 of grain as it comes to the elevator, grinding the samples 

 of wheat in a small mill made for that purpose. He com- 

 pares each bake with that made from a standard flour put 

 out by the mill. 



There is some little difference in the composition of the 

 hard or spring wheat flour of the Northwest and the soft 

 or winter wheat flour, the spring wheat flour being stronger, 

 that is, containing a higher percentage of gluten, the pres- 



