CONTINUOUS BREWING IV. CONTINUOUS FERMENTATION ON THE PILOT SCALE

The construction and operation of an experimental fermentation unit comprising wort storage vessels, metering pumps, continuous fermenters and yeast separating vessels is described. The fermenters, which can be used either individually or connected together, are equipped with stirrers and with facilities for controlling the temperature. By means of a vertical overflow pipe sliding through a gland in the fermenter base, the working capacity of each vessel is adjustable from 3 to 17 gal. During fermentation, the concentration of yeast can be increased by surrounding the overflow pipe with sleeve-like baffles. Examples are given of the effects that strain of yeast, rate of flow of wort, speed of stirring and concentration of yeast have on the composition and rate of production of beer. A system of microbiological tests has been developed to assist in minimizing infection.