21 



packed toi^fether, called the aleiiroue cells. These outer layers and the 

 row of cells taken together form the greater part of the bran. The little 

 eg-g--shaped part at the bottom of the first picture is the germ from which 

 the sprout starts when the grain commences to grow. The remainder of 

 the grain, known as the Eiidospenn^ is made up largely of starch and 

 gluten. From a miller's standpoint, this part of the grain is by far the 



Fig. 25. Cross section of a grain of wheat : (a) outer 

 coverings ; (b) Aleurone cells ; (c) Endosperm, the 

 part of the \\ heat from which the flour is 

 made. 



A part of the section more highly magnified 



most important ; for the object of milling is to separate the endosperm 

 from the rest of the grain and grind it to flour. 



In the roller-process mills of to-day, the wheat usually passes 

 through six pairs of rollers before the grinding is completed. In the first, 

 the miller seeks just to break the grain into pieces. After sifting, the 

 coarse parts, called the "tailings", are passed on to the next pair of 

 rollers, where thev are flattened, and some of the floury substance ground 

 off of them. This is also sifted, and the tailings passed on to the next 

 rollers where the flour is removed, .\fter the wheat has passed through 

 all the rollers in this way, the flattened pieces are almost entirely free 



from flour, and are classed as bran. ^^ ,-~-~_^ 



Figure 26 is a picture of a piece or 

 In all such meth- 



" scale " of bran. 



first ; and, being i^^^S^^k^-i^cJ-^^^^^^ 

 . particles, it makes '0^^^-^^^^m0n 



Fig. ib. A cross section of a piece of bran : (a) outer 



covering of the wheat ; (b) aleurone cells ; (c) 



endosperm. Notice that the endospeiui has 



nut been all ground off from the bran. 



part is rubbed 



free from bran 



very white flour. This forms the 



grade of flour known as "patent." 



That got by grinding closer to the 



bran is known as the "baker's" 



grades. Still closer grinding forms 



the low grades of flour. Generally speaking, the more bran particles there 



are in the flour, the lower it is graded. The outer part of the wheat, nearly 



all of which goes into the bran, contains much more bone making 



material than the flour. Because of this, some say that the " patent " 



and "baker's" grades of flour are not so good as the flour made by 



the old stone process. The Graham flour is supposed to be all of the 



