Topic More on Beer
Orange-colored galls, such as these pictured in 2010, from the beech tree forests of Patagonia have been found to harbor the yeast that makes lager beer possible. Five hundred years ago, in the age of sail and when the trans-Atlantic trade was just beginning, the yeast somehow made its way from Patagonia to the caves and monastery cellars of Bavaria where the first lager beers were fermented.
If you like lager beer, you have Christopher Columbus to thank for it. The
long-standing mystery of where the yeast that makes cold-temperature lager beer
fermentation possible has been solved, in the beech forests of Patagonia
in Argentina.
Humans have been making beer for a very long time. The first actual
evidence we have is barley beer 6,000 years ago in Sumeria, which was probably
somewhat like a thin, fermented, drinkable gruel. In Europe, the same yeast
types used to make bread and wine were used to make ale-type beers,
a process that was well-established by the Middle Ages.
But in the 15th century, something remarkable happened in Bavaria. Beers stored in the cold, dank caves and cellars there,
often by monks, began to ferment. A new type of slow-growing, cold-tolerant
yeast had found its way into the area, making bottom-fermenting beer type
possible for the first time.
Lager has since become so widespread that it is now the most popular
technique for producing alcoholic beverages, with over $250 billion in global
sales in 2008.
The yeast that made all this possible was called Saccharomyces pastorianus, which was a fusion of a
well-known ale-yeast called Saccharomyces cerevisiae and some other, unknown,
cold-tolerant yeast.
However much scientists searched, they couldn’t find the other half of the
yeast fusion in the wild. They looked at the more than 1,000 yeast species known
and found no match. It didn’t appear to exist in anywhere in Europe.
But now an international team of researchers have discovered the home ground
of this magical yeast that has made so many sporting events so much more
enjoyable
It comes from the beech forests of Patagonia, the alpine region at the tip of
South America, they report in this week’s edition of the Proceedings of the
National Academy of Sciences. The yeast lives in galls
that infect the trees there and is a 99.5% match for the ‘missing link’ half of
the lager yeast.
They named the newfound yeast Saccharomyces eubayanus.
“Beech galls are very rich in simple sugars. It’s a sugar rich habitat that
yeast seem to love,” Chris Todd Hittinger, a University of Wisconsin-Madison genetics
professor and a co-author of the study, said in a release.
In fact, the yeast is so active in the galls that they spontaneously ferment.
“When over mature, they fall all together to the (forest) floor where they often
form a thick carpet that has an intense ethanol odor, most probably due to the
hard work of our new Saccharomyces eubayanus,” Diego Libkind of the Institute for Biodiversity
and Environment Research in Bariloche, Argentina, said.
Somehow, and no one knows exactly how, this New World yeast got to Europe
just as the Columbian exchange between Europe and the Americas was
beginning. Perhaps beech wood from Argentina was used to make something that
ended up in a monastery. However it happened, it made its way to where beer was
brewed. And the rest, beer lovers have cause to be grateful for, was
history.
Or as the researchers put it rather more dryly:
The facile recovery of this species from Patagonia suggests that S.
eubayanus may have been absent in Europe until it was imported from
overseas after the advent of trans-Atlantic trade.
Original article:
By Elizabeth Weise, USA TODAY
8/22/2011
This illustration depicts the journey of lager yeast from Patagonia at the southern tip of South America to Europe 500 years ago.
Wonderful views on that!