Agricultural and Biological Engineering Department, University of Florida, Gainesville, Florida, USA.
Food Science and Human Nutrition Department, University of Florida, Gainesville, Florida, USA.
J Food Sci. 2024 Jan;89(1):513-522. doi: 10.1111/1750-3841.16833. Epub 2023 Nov 20.
Belgian Saisons and Lambics are two well-known examples in the brewing industry of mixed fermentations, combination of two or more yeast and/or bacteria strains. The purpose of this study was to determine the impact different pitch rates of Saccharomyces cerevisiae (traditional brewing yeast) and S. cerevisiae var. diastaticus (a variant associated with Belgian styles) had on the fermentation kinetics and concentration of the volatile compounds in the finished beers. A series of brews were performed utilizing ratios of S. cerevisiae and diastaticus. The fermentations were heavily monitored, and a model was used to fit fermentation variables. It was found that mixed fermentations produced behaviors that were predictable and proportional to the mixture ratios. As expected, the pure cultural fermentations of diastaticus had a slower fermentation midpoint (M) at 45.45 h versus 28.28 h for S. cerevisiae with the mixed ones falling in between the two. Flavor and aroma play a key role in the acceptability of beer. The mixed fermentations showed a combination of the two different yeast strains aromatic profiles. When combined, there was a strong linearity between alcohols (R = 0.94), esters (R = 0.89), and the overall total (R = 0.91) volatile compounds. PRACTICAL APPLICATION: Modeling is a widely utilized tool in several different fields. The purpose of this research is to apply modeling techniques to describe the fermentation speed and flavor profile of a mixed fermentation between S. cerevisiae and diastaticus. The equations from this data can be used by brewers for product development purposes to make beers with certain flavor profiles within a desired timeframe.
比利时赛松和拉比克啤酒是酿造行业中两种著名的混合发酵的例子，混合了两种或多种酵母和/或细菌菌株。本研究的目的是确定不同的酿酒酵母（传统酿造酵母）和酿酒酵母变体（与比利时风格相关的变体）的接种率对发酵动力学和成品啤酒中挥发性化合物浓度的影响。利用酿酒酵母和变体的比例进行了一系列酿造。对发酵进行了大量监测，并使用模型拟合发酵变量。结果发现，混合发酵产生的行为可预测且与混合物的比例成正比。正如预期的那样，变体的纯培养发酵的中点（M）为 45.45 h，而酿酒酵母的发酵中点为 28.28 h，混合发酵的发酵中点介于两者之间。风味和香气在啤酒的可接受性中起着关键作用。混合发酵显示出两种不同酵母菌株香气特征的组合。当组合在一起时，醇（R = 0.94）、酯（R = 0.89）和总挥发性化合物（R = 0.91）之间存在很强的线性关系。实际应用：模型是几种不同领域广泛使用的工具。本研究的目的是应用建模技术来描述酿酒酵母和变体之间的混合发酵的发酵速度和风味特征。这些数据的方程可用于酿酒师进行产品开发，以便在所需的时间内生产具有特定风味特征的啤酒。
