COMPARISON OF AMERICAN WHEATS. 
25 
The average protein content of the wheat and of the straight flour 
is compared in Table VI. With all three classes the protein in the 
flour averages about 1 per cent less than in the wheat. 
Table VI. — Average crude-protein content of three classes of wheat and of the 
straight flour made therefrom. 
Class of wheat. 
Number 
of 
samples. 
Crude protein (per 
cent). 
Wheat. 
Straight 
flour. 
215 
323 
394 
10.6 
12.1 
12.9 
9.6 
11.2 
11.9 
932 
11.9 
10.9 
WATER ABSORPTION OF FLOUR. 
The importance of the water-absorbing power of flour in its rela- 
tion to bread-making quality has been mentioned. Figure 20 will 
emphasize what has been said of the connection of water absorption 
with the weight of the baked loaf. It will be observed that as the 
absorptive power increases there is a proportional increase in the 
weight of the loaf, due to the water retained in the bread during 
baking. That under average conditions the proportion of absorbed 
water retained remains practically constant is also shown diagram- 
matically in figure 20. 
In figure 21 a comparison is made of the flour from the five classes 
of wheat under discussion, and it will be observed that the flour from 
the soft white wheat has the lowest average absorption, while the soft 
red winter wheat comes second. The hard wheat classes, including 
the durum, do not show any very great differences, although the hard 
red winter wheat averages slightty lower than the other two classes. 
The extreme range in water absorption is narrowest in the soft wheat 
and widest in the durums. There would seem to be a fairly close 
connection between the gluten content or crude protein and the ab- 
sorptive power of flour, as will be seen by comparing figure 21 with 
figure 18. 
SUMMARY. 
(1) Normal, plump, dry, and sound wheat of all classes yields 
approximately the same percentage of flour. ' Over 80 per cent of 
the samples of each of the three classes of the more common wheats, 
soft and hard red winter and hard red spring, yielded between 67 
and 75 per cent of flour. 
(2) There is a direct relation between milling yield and the mois- 
ture content of wheat, and in a general way the yield varies inversely 
