Sensory Beer Aging

Abstract

A sensory aging of beer occurs during the beer transport to a customer and its storage; this is due to irreversible chemical processes and is manifested by adverse change in the organoleptic character of the beer. Sensory beer aging results in the evolution of the old flavor of the beer, which is a combination of many foreign fl avors and fragrances. The development of substances responsible for these sensory changes (especially carbonyl compounds) can be affected by storage, particularly by access to oxygen, light, vibrations, and temperature of storage. In our study we selected carbonyl compounds which can be regarded as indicators of aging of Czech lager, including 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, furfural and phenylacetaldehyde. We obtained temporal profi les of their evolution under various conditions of storage and the correlation with the development of the old beer fl avor. The time dependences so obtained provided an interesting fact, namely that the product of Maillard reactions during beer aging exhibits a linear increase and the product of Strecker degradation of amino acids show a nonlinear dependence on the length of aging. These findings will be used to create chemico-statistical methods for determining the degree of sensory impairment of beer. The method will be used also for backward determination of storage conditions and even of beer sensorially damaged due to improper storage conditions.