Lagers are boring. When you pop a can of lager beer, you taste the product of closely related strains of Saccharomyces pastorianus. Their genetic variety pales in comparison to the small but diverse group of yeasts used for making ale and wine, which pump out vastly different metabolic by-products and a wide range of flavors. In fact, lagers have looked and tasted much the same for hundreds of years because breeding strains with new brewing characteristics and flavors has proved difficult; the hybrids were effectively sterile. But that is about to change.
This good news harks back to the 15th-century origins of lagers. S. pastorianus appears to have been bred after an accidental cross of two other yeasts in a cool, dark cave in Bavaria when monks began “lagering,” or storing beer. In the 1980s scientists determined the identity of one original parent: Saccharomyces cerevisiae, which is the mother of all yeasts used in baking and brewing. The other remained unknown until 2011, when Diego Libkind, an Argentine microbiologist, identified Saccharomyces eubayanus in the forests of Patagonia as the missing link. Wild S. eubayanus was not well adapted for industrial brewing, but its discovery opened up the possibility of developing new yeast crosses. “Once eubayanus was discovered, things suddenly became very interesting,” says Brian Gibson, who studies brewing yeasts at the VTT Technical Research Center of Finland in Espoo.
Lager lovers can now officially raise a toast because Gibson and his colleagues recently logged the success of re-creating the ancient fling between S. cerevisiae and S. eubayanus. “You can now produce lager yeasts that are very different from one another,” Gibson says. All the resulting hybrids outperformed their parents, producing alcohol faster and at higher concentrations and turning out tastier products, as documented in a paper published in the Journal of Industrial Microbiology & Biotechnology. In particular, they made 4-vinylguaiacol, which resulted in flavors more characteristic of Belgian wheat beers. “The beers have a clovey aroma,” Gibson says. “It's actually quite nice but maybe something we don't always want. The idea is to have a whole range of strains, and you just pick and choose.” The hunt has now turned to finding new yeast unions that gobble up sugar more effectively, potentially creating lower-calorie beers.
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Gibson notes that building up a wide variety of flavorful strains of lagers should be relatively easy, which bodes well for the as yet undisclosed breweries that are adopting the new fermenters. Lager, according to one 2012 estimate, makes up more than three quarters of the U.S. beer market.
