A new hypothesis for the origin of the lager yeast Saccharomyces pastorianus

Abstract

Saccharomyces pastorianus, which is responsible for the production of bottom-fermented lager beer, is a hybrid species that arose from the mating of the top-fermenting ale yeast Saccharomyces cerevisiae and the cold-tolerant Saccharomyces eubayanus around the start of the 17th century. Based on detailed analysis of Central European brewing records, we propose that the critical event for the hybridization was the introduction of top-fermenting S. cerevisiae into an environment where S. eubayanus was present, rather than the other way around. Bottom fermentation in parts of Bavaria preceded the proposed hybridization date by a couple of hundred years and we suggest that this was carried out by mixtures of yeasts, which may have included S. eubayanus. A plausible case can be made that the S. cerevisiae parent came either from the Schwarzach wheat brewery or the city of Einbeck, and the formation of S. pastorianus happened in the Munich Hofbräuhaus between 1602 and 1615 when both wheat beer and lager were brewed contemporaneously. We also describe how the distribution of strains from the Munich Spaten brewery, and the development by Hansen and Linder of methods for producing pure starter cultures, facilitated the global spread of the Bavarian S. pastorianus lineages.

Wild Patagonian yeast improve the evolutionary potential of novel interspecific hybrid strains for Lager brewing

“…We now know that domestication over the last 500 years has generated Lager yeast strains with the unique ability to rapidly ferment at lower temperatures resulting in a crisp flavour profile and efficient sedimentation, improving the clarity of the final product. However, the genetic diversity of commercial Lager yeast strains is extremely limited, mainly due to the standardization of industrial Lager production during the nineteenth century in Germany (Gallone et al, 2019; Hutzler et al, 2023). This gave rise to only two genetically distinct S. pastorianus subgroups, Group 1 strains (‘Saaz’) and Group 2 strains (‘Frohberg’).…”

“…Lager yeast hybrids experienced an intense domestication process through selection and re-pitching during beer fermentation since the 17 th century (Gallone et al, 2019; Gorter De Vries, Pronk, et al, 2019; Hutzler et al, 2023; Langdon et al, 2019; Okuno et al, 2015), a process similar to experimental evolution (Gibson et al, 2020; Gorter De Vries, Voskamp, et al, 2019). Experimental evolution with microbes is a powerful tool to study adaptive responses to selection under environmental constraints (Barrick & Lenski, 2013; Cooper, 2018; Maddamsetti et al, 2015; Payen & Dunham, 2016).…”

Wild Patagonian yeast improve the evolutionary potential of novel interspecific hybrid strains for lager brewing

“…We now know that domestication over the last 500 years has generated lager yeast strains with the unique ability to rapidly ferment at lower temperatures resulting in a crisp flavour profile and efficient sedimentation, improving the clarity of the final product. However, the genetic diversity of commercial lager yeast strains is extremely limited, mainly due to the standardization of industrial lager production during the nineteenth century in Germany [9,12]. This gave rise to only two genetically distinct S. pastorianus subgroups, Group 1 strains ('Saaz') and Group 2 strains ('Frohberg').…”

“…Lager yeast hybrids experienced an intense domestication process through selection and re-pitching during beer fermentation since the 17 th century [9,10,12,19,20], a process similar to experimental evolution [21,22]. Experimental evolution with microbes is a powerful tool to study adaptive responses to selection under environmental constraints [23][24][25][26].…”

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“…We now know that domestication over the last 500 years has generated lager yeast strains with the unique ability to rapidly ferment at lower temperatures resulting in a crisp flavour profile and efficient sedimentation, improving the clarity of the final product. However, the genetic diversity of commercial lager yeast strains is extremely limited, mainly due to the standardization of industrial lager production during the nineteenth century in Germany [9,12]. This gave rise to only two genetically distinct S. pastorianus subgroups, Group 1 strains ('Saaz') and Group 2 strains ('Frohberg').…”