08/22/2011 04:43 pm ET | Updated Oct 22, 2011

The Birth Of Beer: German Lager Traced To South America

This is the story of a stowaway -- a microscopic spore, about 500 years ago, that somehow hitched a ride from South America and ended up 7,000 miles away in Bavaria.

That would be the end of it, except that the spore was a species of yeast that happened to like cold weather. And Bavaria, with its cool climate, is the home of lager beer, perhaps the most popular alcoholic beverage in the world today. It would not have been possible without the mysterious arrival of that yeast, which found its way into long-ago breweries.