The influence of wort aeration and yeast preoxygenation on beer staling processes

125th Anniversary Review: The Non-Biological Instability of Beer

“…Saison et al 123,124,126 found that volatile aldehydes were removed almost entirely by yeast in fermentation, again drawing into doubt the significance of upstream oxidation from a perspective of flavour instability. It has been stressed that there is no advantage in oxygenating yeast directly to avoid aerating wort prior to pitching -the short contact times of oxygen with wort are insignificant 41 . Others have drawn the opposite conclusion 99 .…”

Mitochondrial‐morphology‐targeted breeding of industrial yeast strains for alcohol fermentation

“…Therefore yeasts that produce alcohol during fermentation are exposed to long‐term anaerobiosis. However, a certain O 2 level is required in the early phase of alcohol fermentation [4–6] for sound fermentation. Indeed, O 2 addition is used to increase the fermentation rate in the case of sluggish fermentation under oenological (winemaking) conditions, and it has been confirmed that this effect is efficient only at the end of the cell growth phase [7].…”

“…It has also been reported that the aeration process during fermentation results in decreased production of such flavours as are produced by isoamyl acetate, ethyl acetate or ethyl hexanoate (caproate) in sake [1], or isoamyl acetate in beer [4], through synthesis of unsaturated fatty acid, or improved biomass synthesis in wine through synthesis and oxidative degradation of ergosterols [14].…”

Prediction of the ageing of commercial lager beer during storage based on the degradation of iso-α-acids

“…The use of forced ageing protocols is advantageous as it allows measuring the impact of technological variables on chemical mechanisms, enabling the mimicking of modifications in controlled laboratory conditions and obtaining relevant compositional information in a short period of time. Nevertheless, it is important to underline that thermal treatment of beer could be the origin of a disproportionate development of staling compounds when compared with natural ageing …”

“…Nevertheless, it is important to underline that thermal treatment of beer could be the origin of a disproportionate development of staling compounds when compared with natural ageing. 22 A kinetic study could be performed to gather more information regarding the relationship between the quantities of iso-α-acids, storage temperature and the shelf life period. These models are very important for understanding the extent of a specific chemical reaction and the rate at which changes occur and also to be able to optimise food processing or storage conditions.…”