10 



BULLETIN 328, U. S. DEPARTMENT OF AGRICULTURE. 



sisting of 0.5 per cent of wild oats and 1 per cent of pigeon grass and 

 other weed seed. This wheat was obtained from a farmer's wagon 

 as the grain was unloaded at a country elevator. Because the grain 

 buyer considered wild vetch an inseparable impurity which would 

 injure the milling qualities of the wheat, the farmer was given a 

 lower price for his grain than he would have received had the wheat 

 been free from vetch seed. 



COMPARATIVE MILLING YIELDS OF WHEAT AND OF ITS IMPURITIES. 



Table III shows the yields of bran, shorts, and straight flour ob- 

 tained in milling wheat in comparison with the yields of these products 

 obtained in milling rye, corn cockle, kinghead, and hairy vetch as used 

 in the milling and baking tests. Averages are given of three tests with 

 wheat and corn cockle and of two tests with rye, kinghead, and hairy 

 vetch. 



Table III.- — Milling tests of wheat, rye, corn cockle, kinghead, and hairy vetch, showiiig 

 comparative yields of straight flour , bran, and shorts. 



Ingredient. 



Bran. 



Shorts. 



Straight 

 flour. 



Quantity 

 milled. 



Machine used in milling. 



color of flour. 



Wheat 



Per cent. 

 12.5 

 13.6 

 22.9 

 52.3 

 12.9 



Per cent. 

 14.7 

 31.3 

 28.0 

 31.9 

 25.3 



Per cent. 

 71.4 

 47.8 

 47.6 

 15.8 

 57.8 



Pounds. 



120 



113 



20 



5 



5 





White. 



Rye.. 



do 



Gray. 

 Bluish white. 



Corn cockle . . 



Small experimental mill 



do 



Hairy vetch.. 



do 









A relatively low yield of flour was secured when each impurity 

 was milled by itself, especially in the test with kinghead seed, from* 

 which less than 16 per cent of flour was obtained. The presence of 

 more than 1 per cent of this impurity in wheat as milled resulted in 

 a noticeably decreased flour yield, as shown in Table IV. 



Although the flour from each impurity was difficult to bolt when 

 milled alone, when the mixtures of rye, corn cockle, and hairy vetch 

 with wheat were milled the yield of flour was not greatly reduced. 

 In all probability the wheat flour aided in bolting through a greater 

 proportion of the flour from each of the impurities. On account of 

 the decidedly different color of the flour of each impurity from that 

 of wheat flour, the detrimental effects on the color of the bread made 

 from such flour mixtures are very noticeable. (See Table IV.) 



MILLING AND BAKING TESTS OF WHEAT CONTAINING IMPURITIES. 



TESTS WITH ADMIXTURES OF VARIOUS PERCENTAGES OF EACH IMPURITY. 



Table IV gives the results of milling and baking tests with samples 

 of wheat containing certain percentages of the so-called inseparable 

 impurities — rye, corn cockle, kinghead, and hairy- vetch seed. These 

 data are the averages of tests covering three years with rye, kinghead, 

 and corn cockle, with the exception of the tests with 5 per cent and 10 



