Production of Lambic-like Fruit Sour Beer with Lachancea thermotolerans

Consumer demand for low-alcohol acidic beers is driving the use of non-conventional yeasts in the brewing process. In this study, the addition of mixed berries and fermentation with <i>L. thermotolerans</i> L31 are performed in crafting a low-alcohol acidic beer. Four different beers were brewed in the primary stage with either <i>Saccharomyces cerevisiae</i> or <i>L. thermotolerans</i> and with or without added berry mixture. Beer was fermented for 8 days at 20 °C, stored, and bottled. pH, density, alcoholic content, bitterness, and color of final beer were analyzed for all samples using analytical methods. Volatile compounds, anthocyanin content, and antioxidant activity were also evaluated. Sensory analysis was performed and correlated (PCA) with the analytical results. The obtained data indicated that beers brewed with <i>L. thermotolerans</i> were significantly more acidic and less bitter than <i>S. cerevisiae</i> beers. No difference in alcoholic content was found. Fruity aroma-associated compounds were present in <i>L. thermotolerans</i> beers, which correlated with the sensory analysis. Fruit beers were also redder and showed higher anthocyanin content and stronger antioxidant activity due to the presence of anthocyanins such as cyanidin, delphinidin, and malvidin from fruit, and other antioxidant compounds.