Microbiological Aspects of a Mixed Yeast-Bacterial Fermentation in the Production of a Special Belgian Acidic Ale

Abstract

The evolution of the microbial population during the industrial fermentation of a Belgian acidic ale was followed, and the most important micro‐organisms were identified. In essence, the process can be considered to be a tandem fermentation, as a period of ethanolic fermentation is followed by a period of lactic acid fermentation. The process consists of three stages. The first stage is a seven day fermentation mainly by Saccharomyces; the second is a four to five week fermentation in which Lactobacilli become important; in the third stage a twenty to twenty‐four month fermentation in cask, Brettanomyces species, Lactobacilli, Pediococcus parvulus and Acetic Acid bacteria are all present. The evolution of the Brettanomyces‐Pediococcus coculture during the tertiary fermentation shows a remarkable similarity with the evolution during a gueuze fermentation.

The Role and Use of Non-Saccharomyces Yeasts in Wine Production

“…Brettanomyces spp. have also been implicated in Belgian acidic ale production where it is found in the final 20 to 24 month stage in the fermentation casks (Martens et al, 1997). While the deliberate inoculation of Brettanomyces in must or wine for commercial production has not been reported, some winemakers are working with the indigenous populations of Brettanomyces found in their cellars to make more complex wines, some of which are highly regarded because of their aromas and flavours (Arvik & Henick-Kling, 2002).…”

The Microbiology of Malting and Brewing

“…These beers are inoculated with a mixture of S. cerevisiae, Lactobacillus spp., and Pediococcus spp. and fermented in steel tanks for 7 to 8 weeks to create a fruity, refreshingly tart beer (205). Some breweries package and sell this young beer as is, while others mature the beer for 1 to 2 years in large oak casks, where Brettanomyces spp.…”

“…Some breweries package and sell this young beer as is, while others mature the beer for 1 to 2 years in large oak casks, where Brettanomyces spp. and wild yeasts resident in the wood re-ferment the beer (205). The fully matured beer is then packaged straight, blended with some proportion of young, steel-fermented beer, or filtered and blended with non-sour ale prior to distribution, depending upon the preference of the brewery.…”

Assessing Genetic Diversity among Brettanomyces Yeasts by DNA Fingerprinting and Whole-Genome Sequencing

“…Spoilage of wine by B. bruxellensis is, in fact, considered the most important microbiological issue in the wine industry (5). However, the same species is a beneficial and even crucial contributor to the production of certain specialty beers, such as lambic and gueuze beers, which are typified by the flavors generated during secondary fermentation by this yeast (6,7). Additionally, the species is of increasing relevance for the biofuel industry (8).…”