Wood Aging of Beer. Part II: Influence of Wood Aging Parameters on Monophenol Concentrations

Abstract

Wood aging of beer is an old tradition that is gaining interest from brewers looking for new, innovative products. In this article, a variety of process parameters that could influence the resulting flavor and monophenol concentrations in beer was investigated in model solution. The concentrations of nine of the studied monophenols increased quasilinearly with increasing amounts of oak chips. The extraction of these monophenols is enhanced by low pH (pH 3.5) and high ethanol content (8 and 10% [v/v]) of the extraction medium and relatively high storage temperature (20°C). On the other hand, the presence of oxygen and yeast caused decreases of acetovanillone, acetosyringone, and phenolic aldehyde concentrations. Finally, a summary of the results provides insight into the origin and formation mechanisms of the studied monophenols during wood aging.