A Study of American Beers and AlesRiley, James Garfield
Science
A Study of American Beers and Ales
Riley, James Garfield
Ale -- United States; Beer -- United States; Brewing industry -- United States
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 optional volumetric
method (ibid., p. 4). The uranium acetate method given 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]
[Footnote 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 satisfactory 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.]
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 calculation 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 multiplied 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 appreciable change in the volume of the wort
during fermentation.
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