A STUDY OF AMERICAN BEERS AND ALES. 3 



METHODS OF ANALYSIS. 



The methods of analysis used were those given in Bulletin 107, 

 revised (U. S. Dept. Agr., Bur. Chem.), pages 90-94, with the exception 

 that the determination of phosphoric acid was made by the method 

 used in fertilizer analysis (ibid., pp. 2-5), destroying the organic 

 material in the beer by digestion with strong sulphuric acid and 

 nitric acid and determining the phosphoric acid finally by the op- 

 tional volumetric method (ibid., p. 4). The uranium acetate method 

 Ddven for beers was not used, for the reason that it was found to be 

 exceedingly difficult to obtain accurate results on dark-colored beers. 1 



It was found in the estimation of dextrin by the Sachsse-Allihn 

 method (ibid., p. 91) that there is an error in the method of cal- 

 culation of the amount of dextrose formed from the amount of 

 maltose in the original beer. Instead of multiplying the amount 

 of maltose in the original beer by the factor 0.9, it should be multi- 

 plied by the factor 1.053, as 1 gram of anhydrous maltose yields, on 

 hydrolysis, 1.053 grams of dextrose. The product is the quantity 

 which should be subtracted from the total amount of dextrose found 

 after hydrolysis. The extract in the beer was determined by use of 

 the tables of Schultz and Ostermann (ibid., pp. 209-213). The same 

 methods were used in the analyses of the worts as were used in the 

 examination of the beers. 



RESULTS OF ANALYSIS. 



Tables I to IV contain the results of the analyses of the worts and 

 finished fermented products obtained at the various breweries where 

 this investigation was conducted, arranged so as to show readily the 

 changes which took place during fermentation and, in a few cases, 

 the changes which took place during storage. The results are all 

 given in terms of grams per 100 cc, so that a direct comparison of 

 the quantities of any particular ingredient in a definite volume of 

 material may be made. The comparison of the grams per 100 cc 

 of an ingredient in the wort, with the grams per 100 cc in the finished 

 fermented product, is based on the assumption that there is no appre- 

 ciable change in the volume of the wort during fermentation. 



In Table I are given the results of the analyses of 7 malt worts and 

 the beers produced from them. Table II contains the results of the 

 analyses of 2 malt-and-rice worts and 2 malt-and-corn worts, and 



1 Riley, in his report to the Association of Official Agricultural Chemists for the year 1913, stated that 

 the method giving the most uniform results was that of ashing the beer with an excess of standard calcium 

 acetate, and that while the moist combustion method in the hands of those familiar with it gave satisfac- 

 tory results, the various collaborators working with the method did not get as uniform results as with the 

 method of ashing with calcium acetate. J. Assoc. Off. Agr. Chemists 1 (1915), 138-143. 



