Technological strategies for controlling aldehyde formation in beer: a review of brewing-related flavour instability

Abstract

Flavour stability is a critical quality parameter in brewing, with major implications for shelf-life, consumer satisfaction and global beer distribution. In particular lager beers are prone to flavour deterioration due to their delicate aroma profile. Essential to this deterioration is the accumulation of volatile aldehydes, which are primarily responsible for the stale flavour perceived in aged beer. These compounds originate from multiple chemical pathways, including Maillard reactions, Strecker degradation and oxidation of amino acids, humulones and lipids, all of which are influenced by raw material composition and brewing conditions. This review presents a state-of-the-art overview of aldehyde-driven flavour instability in beer, highlighting the formation mechanisms and, in particular, the impact of brewing operations across the production chain. Critical control points are examined from malt modification, mashing temperature, wort boiling and yeast metabolism, through to downstream processing and packaging. Emphasis is given to the role of heat, oxygen and transition metal ions, alongside yeast activity and sulphite dynamics. Innovative strategies such as the removal of prooxidative metal ions, use of antioxidant-rich ingredients are discussed. Additionally, the review outlines advances in packaging technologies aimed at minimising oxygen ingress and light exposure. This review provides an up-to-date synthesis of brewing operations that affect flavour stability, offering a practical framework for mitigating aldehyde-driven staling throughout the beer production chain.