Evaluation of Non-Saccharomyces Yeast for Low-Alcohol Beer Production

Among many methods to produce low/no-alcohol beers, using special yeasts has gained a substantial interest in the brewing industry. This approach relies on the fact that many non-Saccharomyces yeasts do not utilize maltose, which is the main sugar found in brewer's wort. Additionally, these yeasts may allow the production of a beer with unique sensory characteristics. The aim of the study was to evaluate the potential of 18 non-Saccharomyces yeast strains in the production of low-alcohol beer. As a control strain, S. cerevisiae US-05 was used. The study consisted of two parts: microbiological evaluation and small-scale fermentations. In the microbiological part, ability to ferment sugars found in a wort, resistance to stress factors, phenolic off-flavor production, and enzymatic activities of beta-glucosidase and beta-lyase were evaluated. In the second part of the study, yeasts were used to produce a beer from 9.3 degrees Plato wort. During the fermentation, its dynamics was analyzed. The obtained beers were analyzed regarding their alcohol content, pH, acidity, and color. All of the evaluated strains produced low levels of alcohol. Two of the evaluated strains were characterized by especially high beta-glucosidase activity. Based on the obtained results, six of the evaluated strains are promising in brewing.