Tibetan origins of lager yeast?

Vectored from Current Biology via Ed’s Beer Site:

It has been clear that the lager yeast is a hybrid with one portion of its genome having originated from S. cerevisiae ale yeast [2] . However, the source of the non-ale subgenome, which endows lager yeast with cold tolerance, had been a matter of debate [3] . Recently, a Patagonian origin hypothesis of lager yeast has been proposed based on the discovery of a new cryotolerant Saccharomyces species from Patagonian native forests of Argentina [4] . This yeast, named S. eubayanus, exhibited the closest known match (99.56%) to the non-ale portion of lager yeast and, thus, was believed to be its progenitor. However, we now show that this yeast species is likely native to the Tibetan Plateau. One of the Tibetan populations of the species exhibits closer affinity with lager yeast than the Patagonian population as inferred from population genetics and genome sequence analyses. We thus provide strong evidence for a Far East Asian origin hypothesis of lager yeast, which apparently corresponds better with geography and world trade history.

Pretty cool – and much more intuitive than a Patagonian origin, what with the aforementioned geography and history (maybe it traveled via a horsehide bagful of kumis strapped to some Mongolian saddle?), and also what with China as a possible origination point for the Saccharomyces species.

Hardly scientific, but Tibetan monks and bock-brewing Franciscans in the Alps make a pleasing kind of cultural symmetry. Plus: yetis.


reader question: British ale fermentation techniques

Reader and Berliner Weisse brewer Scott hit me with this recently, and it was too chewy to not repost here:

So I recently came across this thread on Homebrew Talk ( http://www.homebrewtalk.com/f163/british-yeasts-fermentation-temps-profiles-cybi-other-thoughts-221817/).

Anyway, my initial question has less to do with the subject of the thread (ferm temps) but more to do with something one of the responders noted.   His premise was that for lack of a better term “head pressure” during fermentation didn’t allow full expression by some of these British yeasts.  He advocated an “open” or “semi-open” fermentation.  I was wondering what your thoughts on this subject matter?  Would a closed environment have an off affect than an open free release of gases environment?

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