Non-conventional yeasts as a tool for the production of low-alcohol and alcohol free beer

Department of Wine and beer technology, University of Food Technologies-Plovdiv, 26 Maritsa blvrd, Plovdiv, Bulgaria

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Abstract

The global trend for the production of beverages with reduced alcohol content is a result of both consumer desire for a healthy lifestyle and the producers’ efforts to innovate their product portfolios. Although low alcohol and alcohol free beers are traditionally obtained by physical methods, non- conventional yeast strains that are unable to metabolize maltose has been studied extensively for the production of beer with reduced alcohol content. This paper investigated the possibilities of four non- conventional yeast species: Saccharomycodes ludwigii, Zygosaccharomyces bailii, Saccharomyces bayanus ( S. oviformis), and Metschnikowia pulcherrima for the production of low- and non-alcoholic beers at fermentation temperature of 15 °C. The strains displayed markedly different fermentation dynamics. Z. bailii produced the lowest ethanol concentrations and exhibited minimal sugar utilisation, making it suitable for alcohol-free brewing. S. ludwigii generated low ethanol and stable ester concentrations, while effectively reducing aldehydes. M. pulcherrima produced distinctive fruity esters and moderate ethanol levels. S. oviformis produced higher ethanol and citrus-like aromas, making it better suited for low-alcohol beer. Sensory analysis confirmed the chemical trends and highlighted the distinct aromatic signatures of each strain. The findings demonstrate that these yeast species can be selected to produce low- or alcohol-free beers with desirable flavour profiles.