Munich. Year 1602. At the court of Maximilian I, called "the Great", Duke and Elector of the Holy Roman Empire, there was an atmosphere of joy. Despite the fact that his reign would be marked by the 30 Years War (1618-1648), before taking up arms there was still time for happier occupations. Happiness to which, surely, the invention of one of the most popular drinks in history contributed.
Beer has been around since ancient times. Elamites, Egyptians and Sumerians already drank it thousands of years ago. Archaeologists have recently discovered evidence showing that this concoction was already being made in the eastern Mediterranean around 13,000 years ago.
From its origins until the beginning of the 20th century, the typical beer produced was ale, which uses top-fermenting yeasts. Currently, however, the most common lager is lager (bottom fermented), which represents approximately 90% of the beer consumed annually.
The beginnings of this change came when a new species of yeast, Saccharomyces pastorianus or "lager yeast", appeared in Germany in the late Middle Ages. This is a hybrid species that arose at the beginning of the 17th century from the cross between Saccharomyces cerevisiae and Saccharomyces eubayanus, more tolerant to cold.
Until now, however, no one had figured out how this combination came to be. So researchers at the Technical University of Munich combined historical records with contemporary phylogenomic analyzes to find the origins of this yeast hybridization in Maximilian the Great's court brewery (Hofbräuhaus).
The general assumption was that the hybrid arose when a traditional beer fermentation of S. cerevisiae became contaminated with wild yeasts, including S. eubayanus. But experts now believe that this route is rather dubious. Reviewing literature on brewing in Central Europe, they discovered that "lager-style" fermentation had occurred in Bavaria for at least two hundred years.
The hypothesis of the team led by Mathias Huzler is that it was S. cerevisiae that contaminated a batch of beer made with S. eubayanus, and not the other way around. And in intriguing detective work, they identified what they believe to be the source of the contaminating S. cerevisiae: a wheat brewery in the small Bavarian town of Schwarzach, they explain in an article published in the journal FEMS Yeast Research.
Beer has always been a valuable commodity and its production has been carefully regulated. In Bavaria, an ordinance from 1516 (the famous reinheitsgebot) only allowed bottom fermentation and "lager-style" brewing. But in neighboring Bohemia an excellent wheat beer made from S. cerevisiae was produced and large quantities of it were imported into Bavaria.
To limit the economic damage of these imports, in 1548 the ruler Wilhelm IV granted Baron Hans VI von Degenberg a special privilege to brew and sell wheat beer in the border regions with Bohemia. Decades later, Hans von Degenberg's grandson was left without issue and the family died out.
At that time, around 1602, the new Bavarian ruler, Maximilian the Great, seized the special privilege of wheat beer and took over the von Degenberg factories in Schwarzach. In October of that year, the yeast was brought to the Duke's court brewery in Munich, where the famous hybridization would have taken place.
From here, Bavarian S. pastorianus strains spread throughout Europe and are the source of all modern lager yeast strains. The research results suggest that the dominance of the new yeast developed in three stages. First, the S. cerevisiae yeast strain came to Munich from Bohemia, where brewers had been brewing wheat beer since at least the 14th century.
Secondly, the S. cerevisiae that was introduced into the Munich brewery and in 1602 mated with the S. eubayanus, which was already involved in brewing in the style of this city, to give rise to S. pastorianus. And finally, the new yeast was distributed first to local breweries, and then throughout Europe and the world.
“There is a certain irony in that it was Hans VIII von Degenberg's inability to produce a son that triggered the events that led to the creation of lager yeast,” says Mathias Hutzler. “As one lineage died out, another began… without an heir,” he concludes.
