Posted in Beer News

Lager Yeast Mystery Solved!

Lager yeast. We know it. We use it.  Lagers built the American beer scene.  They are the drink of choice at just about every sporting event you’ve ever stepped foot in.  The true biological origin of the lager yeast however, has been a mystery since it’s appearance.

What we used to know.

The cold tolerant yeast is called Saccharomyces pastorianus.  It’s a fancy scientific name for a FUSION of Saccharomyces cereviase (pic above) and another UNKNOWN yeast.

Well, we know it works.  Who gives a crap?  

Learning where this yeast came from tells us a lot about the origins of beer brewing.  What made this situation interesting was that the other half of the yeast fusion couldn’t be found in the wild.  It’s a scientific “what the hell?”  It’s a bit like trying to find the missing links in human evolution.  Except insert yeast.

The National Academy of Sciences just found the missing link.  After scouring through over 1,000 different yeasts, the little fellas have been discovered – along way from Bavaria.  This secret half comes from the beech forests of Patagonia, tat the tip of South America.  In a Gall tree.  In this tree you’ll find Saccharomyces eubayanus.  Hiding out for 1,000’s of years.  These alien-looking galls (below) hanging from the trees thrive in the simple sugar rich environment of Patagonia.

How did those 2 yeasts hookup?

Trade routes my friend.  Trade routes.  Saccharomyces eubayanus was absent from Europe until the rise of trade routes (like the ones Christopher Columbus used.)   Yeast covered wood & timber was brought from one land to the other, introducing yeasts to new lands.

These yeast balls are a 95.5% match to the unknown half.  That’s enough to convict. [PNAS]

 Pic:  Photo by Diego Libkind, Institute for Biodiversity and Environment Research, Bariloche, Argentina

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