Performance and Sensory Impacts of Brettanomyces Yeasts from Different Origins During Primary and Secondary Beer Fermentations

Brettanomyces yeasts are a feature of uninoculated traditional lambic and farmhouse style ales that undergo extended maturation in wooden barrels, where they contribute to characteristic aroma profiles through production of volatile phenols. Over recent years, the potential of these yeasts to generate unique beers has seen some brewers experiment with them for primary alcoholic fermentation and bottle conditioning. In contrast with the vast knowledge of Saccharomyces cerevisiae strain-level impact on fermentation outcomes and sensory properties of beer, to date there has been little research comparing performance of Brettanomyces strains from different origins. In this study, we evaluated the fermentation performance and sensory impacts of five Brettanomyces strains originally isolated from beer, three from wine and one from soft-drink, in both primary and secondary fermentations. Malt sugar utilization was significantly stronger for beer-origin strains, particularly in primary fermentation, while volatile phenols concentrations were generally higher for non-beer strains. Both factors were important determinants of beer sensory properties, though there was little correspondence between outcomes of primary and secondary fermentations for particular strains. These results underscore the importance of strain selection for brewing applications and contribute to the growing body of knowledge concerning Brettanomyces evolution and domestication.