Enhancing the Production of Sour Beers by Adding Blueberries and Fermenting with <i>Lachancea</i> and <i>Metschnikowia</i>

The increasing demand for alcohol-free craft beers with functional properties and distinctive sensory attributes has motivated the brewing industry to investigate alternative production strategies, such as the application of non-<i>Saccharomyces</i> yeasts, to obtain sour beers while reducing production time and associated costs. This study explores the combined use of <i>Lachancea thermotolerans</i> L31 and <i>Metschnikowia pulcherrima</i> M29 in the production of beers brewed with blueberries or enriched with grape anthocyanin concentrate. Physicochemical parameters such as pH, color, bitterness, total polyphenols, antioxidant capacity, and anthocyanin and volatile profiles were evaluated, and a sensory analysis was performed. The results showed that both the addition of blueberries and that of anthocyanin concentrate and fermentation with <i>Lachancea</i> and <i>Metschnikowia</i> significantly influenced the chemical and sensory properties of the beer. Mainly, pH values decreased from 4.35 to 3.50 and from 3.69 to 3.26, while antioxidant activity increased from 3 to 10 times, depending on the type of yeast and the addition of fruit. Alcohol content remained constant at approximately 5.0% <i>v</i>/<i>v</i>. This strategy allows for the production of beer with a distinctive profile and functional benefits, representing a step forward in craft beer development and opening new avenues for research and innovation in the sector.