Demystifying Brettanomyces bruxellensis: Fermentation kinetics, flavour compound production, and nutrient requirements during wort fermentation

Abstract

Brettanomyces bruxellensis is beginning to gain popularity in the craft brewing industry; however, a lack of research on this yeast and lengthy fermentation times present challenges for brewers. Here eight novel Brettanomyces strains were characterized and two were chosen for secondary and co-pitch fermentations, along with the industry standard BSI Drei. The ester and phenol content of these beers was slightly lower than that found in primary Brettanomyces fermentations. Regardless, mixed fermentations proved to be a viable approach to developing beers with "Brett character" in a shortened timeframe. It was also observed that ester and phenol synthesis peaked around day 14 and near the end of the fermentation, respectively. Furthermore, supplementation of thiamine or various amino acids to the pre-growth or fermentation appeared to have a positive effect on fermentation rate in a strain dependent manner. Overall, these findings will allow brewers to be better informed when developing products using Brettanomyces.