The Secret of German Beer - South American Yeast

Found: cold beer's missing link 

For lager lovers worldwide, it is probably the most highly prized micro-organism in the world. But the identity of the yeast that made cold refreshing beer possible has been a long-standing mystery.

Now scientists believe they have unmasked the microbe - a stowaway that sailed to Europe from the New World 500 years ago. The yeast ended up in the caves and monasteries where beer was brewed in Bavaria. There, it crossed with a distant relative, a yeast used for millennia to make bread and ferment wine and ale. The rest was history.

Lager, first brewed in 15th-century Germany, is now one of the world's most popular alcoholic beverages.

The yeast conferred characteristics that for the first time meant that beer could ferment in the cold.

Writing in the journal Proceedings of the National Academy of Sciences, an international team of researchers describes how they discovered the organism after an exhaustive search. Dubbed Saccharomyces eubayanus, the yeast was traced to Patagonian beech forests at the tip of South America.

It lives on sugar within beech galls, causing spontaneous fermentation that generates alcohol...

Nothing like a cold beer on a hot day, even better if it's served by a pretty girl.  I've developed a fondness for this lager over the past year: