134 PROCEEDINGS OF THE CANADIAN INSTITUTE. 



itself. Dextrine is the first product of diastase — it is, so to speak, the 

 half-way house between starch and sugar. To the brewer it possesses 

 many valuable qualities. It ferments but slowly, lends palate-flavor 

 and body to the beer, and also those keeping qualities so essential to 

 the production of sound stock ales. To the maltose on the other hand, 

 the brewer is indebted for the source of the alcohol which finished 

 beer always contains, in more or less quantity. On the due propor- 

 tion, therefore, between these two bodies, maltose and dextrine, the 

 future history of the beer largely, if not wholly, depends. 



All authorities agree in assigning 14o° F. as the temperature of 

 the malt infusion or mash most favorable to diastatic action, and con- 

 sequently to the production of maltose. But, unfortunately, a great 

 difference of opinion exists amongst the standard authorities as to 

 the temperature most favorable to the increased relative proportion 

 of dextrine to maltose. The English authorities declare in favor of 

 low heats, viz., belov/ 150° F., and the American chemists in favor of 

 high, viz., above 150° F. Now since all diastatic action ceases at a 

 heat of 172° F. — diastase itself being destroyed at that heat, it might 

 reasonably be inferred that as we approached this maximum limit we 

 should find the diastatic action decrease, and if such were the case, 

 only the half-way stage in the conversion of starch, viz. dextrine, would 

 be attained, and the practical test of experience bears this reasoning 

 out. The English chemists base their reason for advocating low heats 

 for the formation of dextrine upon similar chemical considerations ; 

 that, as at very low temperatures diastase is inactive, so by a lower- 

 ing of the mashing tempei-ature we limit the action of diastase to the 

 production of dextrine. But this is not borne out by experiment, 

 and the fallacy lies in confounding the checking of too vigorous 

 quantitative action of diastase by the influence of low temperature 

 with the qualitative and destructive influence of high heats upon the 

 nature of diastase itself. Although 145° F. is the temperature most 

 favorable to diastatic action, yet at that heat the relative proportion 

 of dextrine and maltose vary very considerably with diflTerent malts, 

 and according to the results obtained from a large number 

 of test brews and analyses, made by the writer, seemingly in 

 direct proportion to the diastatic capacity of the malt used. The 

 ordinary standard of diastatic capacity of malt is the absolute amount 

 of starch converted into maltose, at a given temperature, and in a 

 o-iven unit of time, each analyst having to make his own standard, 



