Beyond Sweetness – a Study on Yeast Selection, High-gravity Fermentation, and Glucose Oxidase in Non-alcoholic Beer Production

This study investigates the impact of yeast strain selection, high-gravity (HG) brewing, and glucose oxidase treatment on the fermentation characteristics and sensory profile of non-alcoholic beer (NAB). Three yeast strains were evaluated: two maltose-negative, non-alcoholic strains (SafBrew™ LA-01 and LalBrew® LoNa™) and Saccharomyces cerevisiae W-34/70, which was used in an arrested fermentation approach. The study assessed the advantages of HG brewing in NAB production and explored the application of glucose oxidase (Brewers TasteZyme™ G) to mitigate excessive sweetness.

HG brewing is a widely used technique to improve brewhouse efficiency and increase production volume in full-strength beer production. While the gravity is much higher in this case, an increased gravity and similar production techniques can have comparable beneficial effects in NAB production, even though the high gravities here are lower than those in full-strength beers. These positive effects can still be beneficial for NAB production. By intensifying ester formation and fruity aroma buildup, NAB HG production could typically operate at around 12 °P. This allows brewers to retain the positive effects of HG brewing, such as enhanced aroma and body, while also increasing production volumes.

Both chemical and sensory analyses were conducted to evaluate the influence of HG brewing and glucose oxidase on NAB quality. The results indicated that HG brewing contributed to a fuller mouthfeel and increased ester-driven fruity notes, particularly in non-maltose-metabolizing strains. However, NABs are often perceived as overly sweet due to incomplete fermentation, leading to an unbalanced flavor profile.

To address this, the second phase of the study applied a glucose oxidase enzyme designed to convert glucose into gluconic acid, introducing a mild, natural acidity to counteract excessive sweetness. Results showed a significant reduction in glucose concentration, leading to a more balanced sensory profile with improved freshness and drinkability. This enzymatic approach offers a promising strategy for refining NAB taste without artificial acidification, although artificial acidification may still be required to meet food safety pH requirements.

Overall, this study highlights the potential of HG brewing as a tool to enhance NAB production and quality by leveraging its impact on aroma and body while mitigating traditional full-strength beer challenges. Additionally, glucose oxidase treatment presents an innovative solution for improving flavor balance, making NABs more appealing to consumers. Optimizing yeast selection, fermentation conditions, and enzymatic modulation can significantly contribute to the development of high-quality NABs with enhanced sensory characteristics.