Practical new measures of yeast vitality using pH and conductance probes.
Patino, H., Edelen, C. and Miller, J.
Suggestions for improving the sensitivity of the acidification power test for measuring yeast vitality are presented. The first is a new method of calculating and expressing the results in terms of "cumulative acidification power", which compensates for the logarithmic nature of the pH scale and allows for cases where the pH changes in both directions during the test, while the second is to use whichever is the principal fermentable sugar in the wort normally fermented by the yeast strain concerned, since some yeasts accustomed to worts in which maltose is the main fermentable sugar do not perform so well on the glucose normally used in the test. An alternative vitality test, which measures conductance instead of pH but is otherwise similar to the acidification power test and is equally well correlated with yeast performance, is also described.
Keywords : brewers' yeast fermentation measurement performance pH