The advent of large fermentation and storage vessels has accentuated the age old problem of maintaining the final CO2 content of beer at a constant level for a long period of time. Recently new techniques for CO2 addition and control have been introduced into a number of European breweries which have yielded previously unattainable results and in particular have significantly reduced the deviation of the CO2 level from the set-point. The CarboJET jet carbonator which works on the Bunsen burner principle is described and illustrated. It is claimed that it will completely dissolve CO2 into beer in just over one second provided that the gas pressure is 15 p.s.i. greater than that of the beer. One unit in a U.K. Brewery is currently coping with a throughput of 1600 hl/h and the CO2 is completely dissolved 2.5 m downstream of the addition point. To maintain a constant CO2 level, the carbonated beer must be accurately measured and measured continuously. To achieve a high degree of accuracy the CO2 content of the beer should be measured just after the gas has dissolved completely as there should be no turbulance nor visible gas bubbles at this point. Consequently the CO2 addition and measurement points should be as close as possible. Optimum control is achieved when the CO2 level is measured continuously. A continuous sampler for CO2 in beer is described and illustrated. The output from the Sampler is fed to a mini-computer which controls the rate of CO2 addition. In conclusion, the extent of fluctuations from the desired CO2 level is considerably reduced by using the system outlined in the paper, by maintaining the CO2 addition and sampling points as close as possible and by continuously sampling the carbonated beer.
Keywords: beer carbon dioxide carbonation