A SYSTEM OF CONTINUOUS FERMENTATION*

A description is given of the development stages of a successful type of continuous fermentation plant. In this, provision is made for appropriate wort storage under safe conditions, for sterilization of the wort followed by controlled oxygenation under sterile conditions before entering the plant, for an effective beer cooling and yeast separation afterwards and for appropriate beer storage vessels. In the plant itself a suitable yeast is developed to and maintained at the maximum growth rate for that particular temperature. Beer output can then be smoothly controlled and beer characteristics maintained by adjusting the temperature of the two stirred fermentation vessels in conjunction with corresponding changes in the rate of supply of wort to the plant. No yeast recirculation is employed. All types of top fermentation beer (including strong beers) as well as lager have been produced on the commercial scale without difficulty. There has been close equivalence to the corresponding batch beers, as shown by analyses and by taste as judged by panels and by the public. The system has been installed in four breweries which have at present a total maximum output of 20,000 barrels per week. It has proved flexible in operation. Its use is considered amply justified both on the grounds of economics and maintenance of high beer quality.