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.

酒香酵母属酵母（Brettanomyces yeasts）是未人工接种发酵剂的传统兰比克啤酒与农家风格艾尔啤酒的标志性微生物，这类啤酒多在木桶中进行长期陈酿，酒香酵母属酵母可通过合成挥发性酚类物质，赋予啤酒独特的香气轮廓。近年来，这类酵母在酿造特色风味啤酒中的应用潜力，促使部分酿酒师尝试将其应用于主酒精发酵与瓶中二次熟成环节。相较于酿酒酵母（Saccharomyces cerevisiae）菌株对发酵结局与啤酒感官属性的广泛研究，目前针对不同来源的酒香酵母属菌株性能的对比研究仍较为稀缺。本研究针对5株分离自啤酒、3株分离自葡萄酒、1株分离自软饮料的酒香酵母属菌株，分别评估了其在主发酵与二次发酵中的发酵性能及感官影响。实验数据表明，啤酒来源的菌株对麦芽糖的利用能力显著更强，尤其在主发酵阶段；而非啤酒来源的菌株所产生的挥发性酚类物质浓度普遍更高。上述两项因素均为决定啤酒感官特性的关键变量，但特定菌株在主发酵与二次发酵中的发酵表现相关性较弱。本研究结果凸显了菌株筛选在酿酒应用中的重要价值，同时为不断丰富的酒香酵母属进化与驯化相关研究知识库贡献了新的实证数据。