BOULDER, CO – Scientists at the University of Colorado, in Boulder have discovered the ancestor of the lager yeast that first appeared in Europe 600 years ago.
Geneticists have wondered what was the origin of lager yeast that first appeared in Germany 600 years ago. They knew it was hybridized from ale yeast – used to brew ale. But lager yeast ferments at lower temperatures than ale, so scientists have always wondered where did that yeast come from.
The scientists knew that the yeast they had been looking for was out there, somewhere, so they set about to find it. They felt that their best bet was an organism called S. eubayanus.
An article in the Los Angeles Times website reports:
Geneticists have known since the 1980s that the yeast brewers use to make lager, S. pastorianus, was a hybrid of two yeast species: S. cerevisiae — used to make ales, wine and bread — and some other, unidentified organism.
One of the team’s members was Diego Libkind from the Institute for Biodiversity and Environment Research in Bariloche, Argentina. One of the places they were looking was in abnormal growths from trees called galls.
Libkind discovered S. eubayanus in Patagonia in galls on southern beech trees. These galls were rich in sugar and, thus, were good candidates for yeasts to colonize.
As it turned out, these galls were used by Patagonian natives to make a fermented beverage.
When the organism was brought back to the lab and analyzed, it was discovered that its genome was a 99.5% match to what they were looking for.
Lager was invented in the 1400s near the time when Columbus discovered the new world. It is not clear to the team of scientists exactly how it traveled from Argentina to Europe, but that must be another story.
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