Friday, September 12th, 2008

The Evolution of Beer

Art by Molly Ashford.

In the world of beer, ales are separated from lagers by their yeast. Lager yeast collects on the bottom of the fermenting vessel and ferments sugars into alcohol at lower temperatures that ale yeast, which operates at higher temperatures at the top of the fermentation vat. In new research published this week in the journal Genome Research, scientists examined the genetic sequences of 17 unique lager yeast strains from breweries in Europe and North America, tracing variations in the genetic code of those yeasts back through time. The researchers found that a key hybridization step, in which genetic information from two different yeasts combined and rearranged to yield a new 'lager yeast' organism, may have actually happened twice. The researchers found two different family groupings in the lager yeasts they studied, with one lineage associated primarily with Carlsberg breweries in Denmark and breweries in what is now Czechoslovakia, and the other family grouping connected mainly to breweries in the Netherlands, including Heineken. In this segment, we'll talk with one of the authors of the study about genetics and beer, and about the genes behind lager beer styles such as Pilsners, Märzen, Dortmunders, and Bocks. Cheers!