91 - The Evaluation of Beer Aging

Abstract

Beer contains certain components, which act as protective agents in relation to consumers’ health, such as antioxidants, which decrease over time. The shelf life of package beer is determined to a large extent by the appearance of haze or deterioration of the flavor. A comprehensive understanding of the mechanisms involved in beer instability has yet to be achieved. The raw materials are considered the main source of haze precursors, although the brewing process also has effects. Flavor stability depends on the oxygen content of the packaged beer, which gives rise to active oxygen species. The process of beer aging in the package is discussed with the aim of evaluating the various methods found in the literature for the detection of beer aging. These methods have been classified according to the methodology used, as follows: methodologies to measure one compound or groups of similar compounds, methodologies to detect the time elapsed for appearance of OH• radicals, simulations adding exogenous free radicals to beer, and other methods related to the general properties of sensory analysis and sensors. Correlations between sensory analysis and chemical analysis are emphasized. Attention is given to controversial opinions of authors in relation to compounds with antioxidant properties which retard beer aging. The complexity of the mechanisms and the amount of compounds involved in beer aging is pointed out. The methods that follow the evolution of general properties are considered more closely related to beer aging than those following a single compound. A secondary aim is to shed light on a more holistic understanding of beer aging, the mechanisms of which are at present only poorly understood.