By most historical accounts, lager beer first appeared in Bavaria in the 1400s, perfected by monks who would store their suds in icy alpine caves over the summer. But a new find on the Chile-Argentine border, suggests that isn't the case.
Researchers found traces of the yeast used to make lager beer in residues inside 1,000-year-old ceramic vessels that held fermented beverages, reports Liam Miller at NBC News. If confirmed, the find would mean that Lager beer can trace its origins back to South America, rather than Germany.
For non-zythologists, a little explaining is in order. Beer, or a beverage similar to it, dates as far back as 5,000 years to the Sumerians of Mesopotamia, though archaeologists believe humans were brewing and drinking beer well before that. The Egyptians, Babylonians and other cultures drank beer. In the middle ages, Christian monks began adding hops to beer, creating the flavors familiar to imbibers today.
Most of that historical beer brewing relied on the common yeast strain Saccharomyces cerevisiae, or earlier versions of it. This species of yeast sits at the top of the beverage and ferments sugar into alcohol at room temperature, producing a beer that is called ale.
In the 1400s, however, a new strain of yeast, Saccharomyces pastorianus, found its way into the brewing world. That type of yeast sits at the bottom of the beer and ferments best at temperatures between 40 and 50 degree Fahrenheit, like the icy caves the Bavarian monks stored the beer in. That product is called lager, the crisp, translucent beer category that many of the world's most popular beer brands, including Budweiser, Miller, Coors and Heineken are based on.
As Miller reports, since the 1980s, researchers understood that S. pastorianus was hybrid between the yeast used to make ale and another cold-resistant yeast, but researchers were unable to find that cold-loving wild ancestor anywhere in Europe. In 2011, however, researchers compiling a genetic directory of Saccharomyces yeasts discovered one wild variety that lives in the beech forests of chilly Patagonia, in southern South America, that was a 99.5 percent match with the unknown half of the lager yeast, Sara Reardon reported for Science in 2011. Most researchers are now fairly convinced that species, S. eubayanus, is the mystery ancestor of lager yeast.
The new discovery suggests that humans used S. eubayanus to produce alcohol at least 200 years before Lagers came to Bavaria. The yeasts were found in residues collected at two different sites from vessels used to make plant-based alcoholic beverages.
“This is the first archaeological evidence and earliest evidence of any kind of Saccharomyces eubayanus being used in alcohol production,” archaeologist Alberto Perez of the Universidad Catolica de Temuco in Chile tells Miller. “Our findings confirm the historical presence of the yeast in this region and now we have confirmation of its use.”
So the big question is, how did a yeast from Patagonia make it to Bavarian breweries? The answer is complicated.
In the past six years, researchers have discovered wild strains of eubayanus in Tibet, North Carolina, Wisconsin and close relatives in New Zealand, according to a press release from the University of Wisconsin-Madison last year. The strains from Tibet and North Carolina currently seem to be the closest genetic matches to domesticated lager strain. But the fact that hunter gatherers in South America were using the yeast to make alcohol adds another wrinkle.
“The evidence that Saccharomyces eubayanus may have been used to ferment beverages before contact between the Eastern and Western Hemispheres suggests an intriguing twist to the origin of lager yeasts,” Chris Todd Hittinger, researcher at the University of Wisconsin who was on the team that discovered the yeast in Patagonia, tells Miller. “Future genetic studies will be required to exclude the possibility that these strains are environmental contaminants and to determine how they are related to wild Patagonian strains, wild strains from the Northern Hemisphere, and the domesticated hybrid strains used to brew lagers.”
If the yeast did make its way to Europe directly from South America, researchers believe that it may have come on ship timbers, barrels made from South American trees or on an animal, according to Reardon. Any lager produced in Europe before the yeast's arrival may have used a different strain of yeast. Or perhaps the yeast traveled down the Silk Road from Tibet.
Whatever the case, S. eubayunus has gone on to colonize the entire world, or at least its breweries.