The yeast fungus that makes beer has gone through its own stages of evolution, overseen by brewers over the centuries.
Now, a biologist has sequenced the genome of a key yeast, S. cerevisiae x S. eubayanus hybrids, which produces most modern beer — potentially opening up a whole new world of beer
“There’s going to be a lot of opportunities,” said Chris Hittinger, of the University of Wisconsin–Madison, in an interview with Laboratory Equipment. “It’ll be a question of whether there are better styles out there.”
Two types of beer yeast exist. Ales are the easier-to-brew, naturally occurring strain. But lagers, which are a hybrid, were first to appear in Bavaria in the 1400s.
It was an innovation that caught on. Currently, about 94 percent of the beer in the world is from lager yeast.
Some controversy existed as to whether all lagers shared a single, common ancestor.
Hittinger’s genome work found that two separate hybrid strains had developed in Germany, especially in the 19th to early 20th centuries. The Saaz and Frohberg varieties took comparable but separate evolutionary trajectories, the DNA showed.
“Our findings demonstrate how this industrially important hybrid has been domesticated along similar evolutionary trajectories on multiple occasions,” the University of Wisconsin team wrote, in the journal Molecular Biology and Evolution.
For years, there were no indications of how the hybrid was created, considering the wild components of the yeast had only been found in Patagonia, the southern region of South America.
But recently, other similar wild strains have been found in China and other places in the northern hemisphere, Hittinger said.
No such wild strains have yet been found in Europe, meaning the exact genesis of Saaz and Frohberg remains somewhat of a mystery.
Lagers are generally more work – they need to be brewed at colder temperatures, for a longer time. For instance, many of the microbrews currently made in small batches are the easier-to-make ales, he said.
But lagers’ development was a careful process done over generations – with perhaps a bit of luck thrown in somewhere along the process, he said.
“Like most evolutionary processes, there’s some serendipity,” he said.
But the sequencing of the Saccaromyces genome means that there are a world of possibilities, Hittinger said. Since wild strains exist naturally that have not yet been used in beer making, there could be new flavors and styles that have yet to be discovered.
Already adventurous brewers are starting to branch out, he said. Hittingers’ lab is investigating other yeast types, itself – in addition to looking at their capacity to function as biofuels.
But better beers could be on the horizon – through science, he added.
“It’s going to be interesting to see how consumers are going to react,” Hittinger said. “Ultimately, they’re going to decide whether they like the taste.”