14 STUDIES OF AMERICAN BARLEYS AND MALTS. 



Regarding the relation between extract yield and the percentage 

 of nitrogen, Neumann substantiates Haase's law that an increase of 

 protein is regularly followed by a decrease in extract. His conclu- 

 sions are that a good brewing barley should not only contain a low 

 percentage of protein but should give a high extract yield. Further- 

 more, in high-protein barleys the carbohydrates are more ener- 

 getically consumed in respiration. On the other hand, a good, 

 distiller's barley may be high in protein, but its most essential quality 

 is its high diastatic power. 



Wahl, in his previous writings, has shown that moderately high- 

 protein barleys, when properly malted and brewed, may give even 

 better results than low-protein barleys, as the former are possessed 

 of high vital energy and develop strong enzymatic power during 

 malting, so that the resulting malts are especially rich in both diastase 

 and peptase. The malts from such barleys are not only able to prop- 

 erly saccharify more starch than they themselves contain, but during 

 malting and mashing a comparatively large quantity of protein is 

 rendered soluble by the peptase, the beers produced from such malts 

 being richer in nitrogenous compounds than beers produced from 

 low-protein barley malts. 5 



In his work on malt and beer, Evans c shows that though the nitro- 

 gen question is of importance, it is secondary to the study of the 

 starch conversion products produced during malting and mashing. 

 He intimates, however, that much of the color, flavor, and foam of 

 beer is due to the presence of the nitrogenous constituents. Another 

 investigation of importance which should be mentioned is that of 

 Bleisch and Regensburger, d which showed that the amount of husks 

 increased with the nitrogen, and the loss during malting also grew 

 larger. They advocate the direct determination of the extract as a 

 factor furnishing more reliable data as to the brewing value of bar- 

 ley and malt than does the determination of nitrogen. 



Luff's e work, however, showed no relation between the amount of 

 husks and the percentage of protein. He determined the percentage 

 of husk by treating 150 kernels of barley with 10 cc of 5 per cent 

 ammonium hydroxid in a closed flask, heated in a water bath at 80 C. 

 for one hour. On transferring the kernels from the flask, the husks 

 may easily be separated from the grains. Haase and Bauer f have 

 shown that a winter barley contains more husks than one with a 

 shorter period of growth and a late ripening variety more than an 



Wochenschr. Brau., 1905, 22: 98. 



& Wahl, Amer. Brew. Rev., 1904, 18: 485. 



c J. Inst. Brew., 1906, 12 : 209. 



d Zts. gesam. Brauw., 1905, 28: 628. 



'Ibid., 1898, 21: 603. 



f Wochenschr. Brau., 1907, 24 : 535. 



