Investigating the Evolution of Staling Aldehydes during the Brewing Process and Beer Aging

During storage, beer undergoes a variety of chemical reactions, which lead to unavoidable flavour deterioration. Many of the resulting off-flavours are associated with the presence of the so-called staling aldehydes [1]. Nevertheless, their gradual appearance in the aged beer is poorly understood and the mechanisms responsible for their formation still remain obscure. Staling aldehydes may arise via de novo formation e.g. oxidation of unsaturated fatty acids, Strecker degradation of amino acids and Maillard reactions [2, 3]. Furthermore, aldehydes can be also released from their non-volatile bound-state forms e.g. cysteine or bisulphite adducts. Therefore, to unravel another puzzle piece of the chemistry lying behind the phenomena of beer flavour instability, we have investigated the behaviour of free aldehydes from malt, through the entire process of brewing and fermentation up to beer aging.status: publishe