The influence of yeast strain on the oxidative stability of beer

Flavour stability, or instability, relates to the rate of flavour change through the shelf‐life of packaged beer. There are several control points in the production of beer where flavour stability may be altered. These include fermentation and the influence of yeast is key. Greater insight into the yeast traits which contribute to flavour stability may help yeast strain selection in the future. Knowledge of the key phenotypes may also lead to improved yeast handing or monitoring practices. In this study, 11 yeast strains, previously characterised according to their sensitivity to oxidative stresses (induced by menadione and hydrogen peroxide) were screened using miniature (100 mL) fermentations and the oxidative stability of the resultant green beer assessed using Electron Paramagnetic Resonance Spectroscopy. The selection of strains with high resistance to multiple oxidative stresses was shown to be a good indicator that yeast would produce a more oxidatively stable beer, although the mechanisms determining this are unknown. The relevance of selecting yeast based on their oxidative sensitivity, their potential to remove metals and sulphur dioxide production are discussed.