Sugar Utilization by a Brewing Yeast in Relation to the Growth and Maintenance Phases of Metabolism

In batch fermentations, carried out using a range of conditions, the specific rate of sugar utilization is shown to decline throughout. When yeast mass is increasing, the yield coefficient relating carbohydrate utilization to mass production remains approximately constant and the declining specific fermentation rate parallels declining specific growth rate. When mass production ceases, maintenance of the yeast population requires only a low rate of sugar utilization. Attenuation associated with maintenance phase activity is relatively insignificant compared with that associated with growth.