This conclusion is not entirely in agreement with the results which have been obtained by others upon foreign beers, in the preparation of which low protein barleys have been used. Joseph Race [1] has reported some interesting results of an investigation carried on for the same purpose as that for which this particular investigation was undertaken; that is, to distinguish between all-malt beers and those made from substitutes. His results do not show as sharp a reduction of the protein, but he found in his all-malt beers a very much lower percentage of total protein than was found in the malt beers of this country. He did observe, however, a material reduction of the phosphoric acid due to the use of substitutes. Unfortunately, he made his determination of phosphoric acid in the ash, and while he reports a marked difference between the phosphoric acid content of the malt beers and those made from substitutes, his total figures for phosphoric acid are much lower than those reported in this bulletin. For this reason the figures for total phosphoric acid given by him are not at all comparable with those determined by the moist combustion method, by the uranium acetate method, or by the method of ashing with calcium acetate. [2]
[1] J. Soc. Chem. Ind., 27 (1908), 544-547.
[2] Riley, in his report to the Association of Official Agricultural Chemists for the year 1913, showed that a large proportion of the phosphoric acid was ordinarily lost when the beer was directly ashed (J. Assoc. Off. Agr. Chemists, 1 (1915), 138-143). For this reason, in comparing the amount of phosphoric acid given in the literature on beers, it is very essential to know the method used for determining the phosphoric acid.
The same fact observed by Race, namely, that foreign beers are of low protein content, is shown very clearly in the published literature on European beers in general. König [3] gives the following results of analyses made by himself and H. Weigmann of two all-malt beers, calculated to the basis of a wort containing 15 per cont of solids:
| Beer and percentage of wort. | Protein. | Ash. | Phosphoric acid. |
| Per cent. | Per cent. | Per cent. | |
| Pure Malt Beer: | |||
| 12 per cent wort | 0.548 | 0.259 | 0.098 |
| 14 per cent wort | .457 | .214 | .076 |
From these results of König it will be seen that the protein content of these beers is considerably less than that of the beers examined by the writers. As the phosphoric acid and ash results, however, are practically the same as in American beers, it might be expected that the use of substitutes in place of the low-protein malt would not show so sharp a reduction of the protein as was found by the authors, although one would expect a reduction in phosphoric acid and ash similar to that found in American beers. This is confirmed by the results obtained by Race.
[3] König, F. J., Chemie der Menschlichen Nahrungs- und Genussmittel, 4th ed., v. 1, p. 1154. Berlin, 1903.
Robert Wahl [4] made parallel brewings of a high-protein barley and a low-protein barley, and from these obtained two beers which, when calculated to a uniform wort with 15 per cent of solids, showed a total protein in the beer made from the low-protein malt of 0.734 per cent, and in the beer made from the high-protein malt 1.041 per cent. This clearly indicates that where a beer is made from high-protein barley, as is the case with practically all of the beers made in this country, [5] the reduction in protein by the use of substitutes will be a valuable index to the true nature of the product. This, when taken in connection with the reduction of phosphoric acid brought about by the use of substitutes, gives two factors of value in judging American beers, to determine whether or not substitutes have been used; while in the case of beers made from low-protein barley there is practically only one factor, namely, the reduction of phosphoric acid.
[4] Am. Brewers' Rev., 18 (1904), 339.