Influence of pH and ageing on beer organoleptic properties. A sensory analysis based on AEDA data

Brewers need to know how ageing affects the organoleptic properties of beer. This paper describes sensory assessments of aroma changes in lager beer subjected to accelerated staling (5 days at 40 degreesC at different pH values (4.2 and 4.6), according to a new method for training panellists, based on AEDA results. It shows, for 10 key compounds whose concentrations are known to increase during staling, how modifications in pH affect ageing and perception thereof. In agreement with the AEDA results, "dimethyltrisulphide"-, "trans-2-nonenal"- and "methional"-like perceptions increased significantly as a result of ageing in regular pH 4.2 lager beers. A higher pH led to a smaller age-related intensity increase in the "cardboard" note ("trans-2-nonenal"-like). It also enhanced the "coconut" character ("gamma-nonalactone"-like) but did not change the age-related intensification of the "cabbage" note ("dimethyltrisulphide"-like). Perception of the remaining six compounds ("furaneol"-, "ethyl butyrate", "2-methoxypyrazine", "acetylpyrazine", "beta-damascenone"- and "ethyl cinnamate"-like) did not evolve with ageing or pH. (C) 2004 Elsevier Ltd. All rights reserved.