Biological and Biochemical Aspects of Tower Fermentation*

Biological and biochemical aspects of continuous fermentation in a Tower fermentor operated on a commercial scale are described with particular reference to the rate of utilization of α-amino nitrogen and carbohydrate. Under stable conditions, well defined gradients exist in the Tower fermentor and a fully fermented beer, indistinguishable from the conventional batch beer, is produced. Breakdown of these gradients leads to unstable conditions with a resultant increase in effluent gravity. Yeast growth in the Tower has been shown to be comparable to that of a conventional batch fermentation. No mutation of the yeast has been observed over a period of 3 years, during which time little trouble was experienced from infecting organisms.