Vespucci Connection, Columbian Exchange: The New-World Origins of Old-World Lager Yeast

At Silver Branch, we pride ourselves in bringing to the community a blend of traditional and contemporary styles. Sometimes, the style itself is a blend of something old and something new. The first release of our latest lager series, Vespucci Connection, is just that–a German-style pilsner with the American-associated twist of adding dry hops, often referred to as an Italian pilsner. It seemed appropriate, then, to name such a beer after Amerigo Vespucci, the Italian explorer who in 1501 crossed the Atlantic, bridging the Old World and the New World. His travels were the first to identify South America as a separate continent.

The impact of the early travels of explorers like Christopher Columbus and Amerigo Vespucci to the Americas was huge. The transfer of everything from plants and animals to technology and diseases across the Atlantic in the 15th and 16th centuries is referred to as the Columbian exchange. It is now believed that the Columbian exchange was key in the development of lager beers. No, not because the indiginous peoples of South America were brewing lagers before the Germans, but because lager yeast is a hybrid of two yeast species, and one of the two parent species was only recently found to have originated in Patagonia, the southernmost part of South America. It is this yeast that gives modern lager yeast its cold-tolerance.

Brewer’s yeast is generally categorized as “ale yeast” and “lager yeast”. As most people probably know, the scientific name for ale yeast is Saccharomyces cerevisiae. Less commonly known is that the scientific name for lager yeast is Saccharomyces pastorianus. Interestingly, S. pastorianus is a hybrid of S. cerevisiae and an until-recently unknown cold-tolerant yeast–while S. cerevisiae has 2 sets of chromosomes, S. pastorianus has 3 sets. Ale yeast generally prefers a warmer fermentation temperature, and lagers are as clean and crisp as they are because of the colder fermentation temperatures permitted by the contributions of the extra set of chromosomes from the cold-tolerant yeast to the modern lager yeast hybrid. A 2011 study published in the Proceedings of the National Academies of Sciences by Libkind et al determined that the cold-tolerant parent strain of lager yeast is called Saccharomyces eubayanus, and S. eubayanus has only been found in the wild, despite a lot of searching, in Patagonia.

It is most likely then, that S. eubayanus hitched a ride on a ship leaving South America (maybe even that of Vespucci himself) to Europe, where it found its way into some German brewer’s fermenter. Eventually S. eubayanus merged with S. cerevisiae, and, in a cold Bavarian cave, gave rise to the world’s favorite category of beer, the lager.