2022

Nikulin, Jarkko; Aisala, Heikki; Gibson, Brian

<p>Use of non-conventional yeasts are increasingly seen as a option for the production of low and alcohol-free beers. In this study, the application of four non-conventional yeasts - Kazachstania servazzii, Kluyevoromyces marxianus, Pichia fermentans and Torulaspora delbrueckii, originally isolated from sourdough cultures, for cold contact fermentations was assessed by screening their ability to reduce wort aldehydes at a fermentation temperature of 1.0 ± 0.5°C. Of the evaluated yeasts, Torulaspora delbrueckii was found to be most promising, being capable of the removal of wort-derived aldehyde off-flavours, while being sufficiently sensitive to low temperatures to limit the formation of ethanol. Despite the different alcohol by volume (0.07% vs. 0.28%), the beers produced via cold contact fermentation at 10L scale with T. delbrueckii and a reference lager yeast strain were similar, with no major differences found after sensory analysis. The results suggest that T. delbrueckii could be used in cold contact fermentation to produce non-alcoholic beers with alcohol content at, or close to, 0%.</p>