10 



BULLETIN 557, U. S. DEPARTMENT OF AGRICULTURE. 



/6 



20 



TO TO 



/9.9 2/.9 

 •7 ViS 



W2/&HT FTf? /OOO H , £/5M£l.S-~G/?rfMS 

 22 2* 26 23 30 32 



TO TO TO TO TO TO 



2S.9 27.9 29.9 S/.9 



2S.9 



SS9 



3<3 



TO 



37.S 



FLOUR YIELD AND WEIGHT PER BUSHEL. 



The value of the " weight per bushel " or " test-weight " determi- 

 nation as a rough means of measuring wheat quality has long been 

 recognized by the grain trade, and requirements relating thereto are 

 made in practically all grading rules. The weight of the measured 



bushel of pure 

 wheat is dependent 

 upon the specific 

 gravity, shape, 

 size, and uniform- 

 ity of the kernels. 

 As usually deter- 

 mined, it is affect- 

 ed by impurities, 

 such as weed 

 seeds, dirt, chaff, 

 and other grains. 

 Grade rules in 

 force in a few mar- 

 kets provide that 

 the determination 

 be made on the 

 screened sample, 

 or, in other words, 

 after the larger 

 part of the im- 

 purities have been 

 removed. Generally, however, no such rule is observed. The de- 

 terminations reported here were made with the samples after they 

 had been cleaned and prepared for milling, and the influence of im- 

 purities is reduced to a minimum. It will be found that the figures 

 for this reason are a little higher than those ordinarily secured. 



Among the factors causing variation in the test weight are shriv- 

 eled or shrunken kernels, the various forms of damage usually sus- 

 tained in the field, the moisture content, and varietal differences. 

 The last-mentioned factor is unfortunate and detracts from the 

 value of the test rather than adds to it, as such variations often 

 have little relation to quality. More will be said of this in a fol- 

 lowing paragraph. All the other factors mentioned bear a direct 

 relation to quality. 



That high moisture content is accompanied by low flour yields has 

 been brought out, and as high moisture content is also accompanied 

 by low weight per bushel it is apparent that this determination is 



22 



73 99 /32 /37 S>£ 



*G 



Fig. 7. — Diagram showing the relation between the weight 

 per 1,000 kernels and the flour yield of samples of soft red 

 and hard red winter and hard red spring wheat of the crops 

 of 1911, 1912, and 1913. 



