10 STUDIES OF AMERICAN BARLEYS AND MALTS. 



in nitrogen, than are the well-matured grains found on the main 

 stalks, thus showing that a sample of barley even though coming 

 from a single field and representing one variety may vary much in 

 percentage of protein in individual kernels. 



Schjerning a has studied the growing barley plant with special ref- 

 erence to the nitrogenous compounds, analyzing the plants at three 

 different stages of their development, namely, at green, yellow, and 

 full ripeness. Beginning with the formation of the grain, at green 

 ripeness, he analyzed the berries up to the full-ripe stage and con- 

 cluded that " barley has acquired its full maturity when the con- 

 version of the soluble into insoluble carbohydrates and soluble into 

 insoluble proteins has reached its maximum," and that the ripening 

 of barley is a process tending toward a state of equilibrium in respect 

 to its nitrogenous constituents ; when properly ripened barley is har- 

 vested very little loss due to respiration takes place during storage. 

 Over ripeness is characterized as a loss of substance. He found that 

 on ripening the percentage of soluble nitrogen in the total nitrogen 

 decreased from 45 to 18 and that the amidamin nitrogen decreased 

 from 28 to 5 per cent. Only traces of proteoses and small amounts 

 of peptones were found. He showed that early harvested barley is 

 poorer in protein than the fully matured grain, and that the chemical 

 composition is not influenced by species, variety, or type of barley, 

 but is affected by the character of the soil and climatic conditions. 

 The length of the growing period, cultivation, and climatic conditions 

 influence the nitrogen content also, and therefore the quality of 

 barley can not be determined from the amount of this constituent 

 alone. 



This agrees with the researches of Kukla, & Jalowetz, c Prior/ AVahl, 6 

 and others. These investigators have shown that high protein bar- 

 leys often give a better malt, which produces a better beer than a 

 malt made from a barley of lower nitrogen content. Kukla also 

 concludes that it is not so much the total protein of barley which in- 

 fluences the quality of the beer as it is the character of the nitrogenous 

 compounds. In his important contribution on the chemistry of 

 barley and malt, Prior f has shown that the consideration of the 

 amount of hordein (alcohol-soluble protein) and of the insoluble 

 protein constituents of the endosperm is more important than that 

 of the total protein, which should only be considered when above 13 

 per cent. The hordein he finds located principally near the embryo, 



"Compt. rend, travaux lab., Carlsberg, 1906, 6: 229. 

 6 Zts. gesam. Brauw., 1900, 23: 418. 

 ^Ibid., 1906, 29: 172. 

 d Wochenschr. Brau., 1905, 22: 52. 

 e Amer. Brew. Rev., 1907, 21: 274. 



f Allgein. Zts. Bierbrau. Malzfabr., 1905, 33: 341, 412; through J. Insr. Brew., 

 1906, 12: 159. 



