Inhibition of Beer Volatiles Formation by Carbon Dioxide Pressure¹

1 Presented at the 42nd Annual Meeting, Milwaukee, May 1976.

Abstract

The formation of total volatiles and yeast growth were inversely related to the CO₂ counterpressure applied during 100-liter fermentations. However, the rate of fermentation was relatively unaffected. Thus, 8 psig (22.7 psia) CO₂ counterpressure in a 22°C fermentation repressed both total yeast growth and total volatiles concentration to the levels present in a 15°C fermentation with 0 psig (14.7 psia) CO₂ counterpressure. The repression of individual volatile compounds, however, was not uniform. The influence of temperature, agitation, and CO₂ counterpressure upon the dissolved CO₂ concentration during active fermentation was quantified. It was shown that the degree of supersaturation (termed the supersaturation coefficient), which is the ratio of the dissolved CO₂ concentration during active fermentation to the CO₂ saturation level, was constant over the ranges of temperature and CO₂ counterpressure examined, at constant agitation. The supersaturation coefficient varied inversely and in a linear manner with agitation. At sufficiently high agitation, no CO₂ supersaturation existed during active fermentation, thus the supersaturation coefficient was 1.0.

• Agitation
• Fermentation
• Temperature
• Yeast growth