Early Determinants of Quality in Spontaneously Fermented Beer********

虽然自然发酵的酸啤酒已经生产了几个世纪，但人们对复杂的微生物群落如何相互作用以生产最终产品知之甚少。由于自然发酵的啤酒只能在一年中的特定时间生产，因此使用倾斜培养发酵的方法来重现自然啤酒的尝试很常见。然而，由于缺乏关于发酵过程中微生物演代和相互作用的知识，这些啤酒显然不那么复杂。此外，在制造过程中，由于啤酒质量差而需要丢弃桶，因此损失的比例很高。我们假设，有一些低质量和变质啤酒的早期标志可以被识别出来，并在未来用于识别和清除坏桶。Blind Enthusiasm酿造公司是北美唯一一家专门为生产天然啤酒而建造的工厂，在传统和混合文化方式下生产这种产品方面有着丰富的经验。为了识别低质量啤酒的早期标记以及导致这种损失的因素，我们需要更好地了解发酵过程早期发生的事情。通过这次合作，Blind Enthusiasm和Willing实验室将研究发酵早期阶段的微生物组成和代谢物水平如何预测啤酒的最终质量。我们还将研究酿造过程中的因素，如麦汁中的溶解氧和桶的储存温度，是否对啤酒的发展起作用。此外，细菌和酵母将从发酵啤酒和周围环境中分离出来，以便将来用于混合培养发酵啤酒。

While spontaneously fermented sour beer has been produced for centuries, little is known about how the complex communities of microorganisms interact in order to produce the final product. Due to the fact that spontaneously fermented beer can only be produced during certain times of the year, attempts at recreating spontaneous beer using a method of pitched culture fermentation are common. However, due to the lack of knowledge surrounding microbial succession and interactions during the fermentation, these beers are distinctly less complex. Additionally, there is a high percentage of loss during manufacturing due to barrels which need to be discarded due to poor quality beer. We hypothesize that there are early markers of low quality and spoiled beer that can be identified and used in the future to identify and remove bad barrels. Blind Enthusiasm brewing company has the only purpose built facility for manufacturing spontaneous beer in North America and has a significant amount of experience with the manufacturing of this product in both a traditional and mixed culture manner. In order to identify early markers of low quality beer as well as the factors that lead to this loss we need to better understand what is occurring early in the fermentation process. Through this collaboration, Blind Enthusiasm and the Willing lab will study how the microbial composition and metabolite levels during the early stages of fermentation predict the final quality of the beer. We will also examine whether brewing process factors, such as dissolved oxygen in wort and storage temperature of barrels, play a role in the development of the beer. Additionally, bacteria and yeast will be isolated from the fermenting beer and surrounding environment for future use in mixed culture fermented beers.