From the American Brewers’ Review – February 1910
On The Preservative Action of Phosphoric Acid On Yeast
Moufang. – Wochenschrift für Brauerei
The influence of different waters upon yeast differs widely according to the character of the water. It is a well-known fact that the same yeast type sent to different breweries, may carry on widely different fermentations, and degenerate much more rapidly in one or the other pace. In the explanation of this observation, the water of the respective brewery no doubt is of importance.
Of still greater importance for the yeast than the salts of the brewing water, are the phosphates. The author found that a very dilute solution of phosphoric acid exercises a very favorable influence upon degenerated yeast. After suitable treatment with washing water containing dilute phosphoric acid, the yeast exhibited a materially higher fermenting activity than that which was not so treated, and in general recovered its original good properties. Experiments in treating other yeast that did not show any degeneration, in like manner with water containing phosphoric acid, never failed to show plainly increased fermenting power and the development of more favorable properties. Moreover, it was found that the same yeast which in one case was washed with common water, and kept under the same water, had lost its fermenting capacity almost entirely after twelve to fourteen days, while the same yeast, under the same conditions, in different concentrations of dilute phosphoric acid solution not only maintained its fermenting power, but entered upon the fresh fermentation with almost greater energy than in its original condition before such treatment.
The author finds a possible explanation of this behavior in the fact that the zymase consists of two parts, enzyme and co-enzyme, the latter, after having been decomposed, recovering its activity if phosphates are added. – N. H. C.
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