Effects of Ethanol, Carbonation and Hop Acids on Volatile Delivery in a Model Beer System

Abstract

J. Inst. Brew. 117(1), 74–81, 2011 A model beer was created to investigate the effects of ethanol, carbonation and hop acids on volatile release (ethyl acetate, isoamyl alcohol and phenethyl alcohol) using both headspace analysis and in-nose measurement during consumption. None of the factors were found to impact on equilibrium headspace partitioning, however headspace sampling after short term decanting revealed minor and compound specific effects of each of the components. When measured in-vivo, hop acids had no significant effect on volatile delivery; however ethanol significantly increased the delivery of volatiles during consumption. This increase was sustained throughout the release profile. Carbonation was found to increase the release of ethyl acetate and isoamyl alcohol during the first release peak after swallowing, but had no significant effect on phenethyl alcohol. Furthermore, ethyl acetate was increased by carbonation in the second peak after swallowing, but this effect was not found to be persistent in subsequent peaks. These results indicate a trend between the compound’s air-water partition coefficient and the effects of carbonation in-vivo. The effects of ethanol and carbonation seemed to be independent and therefore an additive effect is possible. This study highlights the difference between data collected by headspace and in-vivo means.