48 
Colorado Experiment Station 
THE CRUSHING STRENGTH OF WHEAT 
After explaining that flinty and mealy wheats differ in their 
structure, in that the mealy kernels contain air-filled spaces which 
reflect the light and cause the berries to appear white and opaque, and 
that the flinty berries, owing to the absence of such air-filled spaces, 
permit the passage of the light and therefore appear translucent or 
flinty, Schindler says that the flinty berries are designated as hard 
wheats and the mealy ones as soft wheats.* This is the clearest def¬ 
inition of these terms that I have met with, but they are not generally 
used with the sharp distinction of this definition. Attempts have been 
made to determine the degrees of hardness of different wheats and use 
the figures obtained as a means of classification. At the California 
Station they determined the weight necessary to- cut the kernels when 
they were placed between the jaws of a pair of pinchers, f At the 
Kansas Station they used a '‘Grain Tester” devised in conjunction 
with Wm. Gaertner & Co., of Chicago, in which they determined the 
weight necessary to crush the kernels when placed under a steel pestle 
in a miniature mortar. § On page 374 of Kansas Bulletin 167, Prof. 
Roberts gives the following basis of classification. “In general we find 
that *soft^ wheats crush under a pressure of 6,000 grams or less GS 
pounds), semi-hard wheats at about 9,000 grams (20 pounds) and hard 
wheats at 12,000 grams and over (26 pounds and over). 
OUR METHOD OF DRYING 
Prof. Roberts dried his samples for seven days at the boiling 
point of water under ordinary atmospheric pressure and preserved them 
in a desiccator till used. I dried our samples at 100° C., under a 
pressure of 75 mm. for 7 hours, corked the bottles tightly and pre¬ 
served them in a desiccator. The object in this drying is to bring all 
of the samples to a common basis in regard to moisture, but it is a 
question whether there is any need of doing this, for the variation in 
moisture at a given locality is not great and this factor adjusts itself if 
wheat is transported from one place to another, and the tests are all 
made at the place of grading. There seems to be a more serious ques¬ 
tion raised by drying than the variation due to the moisture in the 
wheat, i.e., does drying at 100° C., for seven days leave the wheats 
in such a condition that the determination gives us the real crushing 
strength of the sample, or only that which it may chance to show under 
a purely artificial condition? Even this would not be a serious objection 
if we could be sure that all samples deported themselves in a similar 
* Schindler, Der Getreidebau, 1909, p. 151. 
t California Bui. 212, G. W. Shaw and A. J. Gaumnitz, p. 335. 
§ Kansas Bui. 167, H. P. Roberts, "A Quantitative Method for the Determina¬ 
tion of Hardness in Wheat.” 
