Influence of Pasteurising Intensity on Beer Flavour Stability

J. Inst. Brew. 117(4), 587-592, 2011 While it is preferred that flavour improves during the beer maturation process, formation of undesirable flavours inevitably occurs during beer storage. Beer ageing problems occur during beer storage and can damage the beer style, especially for lager beer of a more delicate style. In this research, the impact of pasteurising intensity on beer ageing and flavour stability was studied. Through process adjustments, three types of bottled beer were obtained from one fermenter and classified by their PU values as 2 PU, 8 PU and 14 PU. The dynamic changes of related indices (taken every month) characterizing the ageing and flavour of the beer under different pasteurising intensities were investigated during a 6-month room temperature storage period. The key factors of colour, the thiobarbituric acid (TBA) index, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, bitterness and total polyphenol composition, the concentration of beer volatile compounds (BVCs), and 5-hydroxymethyl furfural (5-HMF) were examined. Statistically, the 14 PU sample showed the highest degree of damage, with the greatest flavour change compared to the other samples.