Actually, this is about the birth of all lager but, saying a lager just sounded better.
The story goes this way. Beer, throughout most of human history, has been ale. When you hear anthropologists speculate that humans came out the hunting grounds and invented agriculture and therefore civilization, it was so they could make beer, they’re talking about ale. When Biblical historians state that “strong drink” in the Bible really meant beer, they’re talking about ale. In fact, any time beer is mentioned before around 500 years ago, it had to be ale because lager simply didn’t exist yet. (If you don’t know or were not aware of the difference between ale and lager check out Ale or Lager – What’s In a Name?)
Until just this month, all that most of us really knew was that lager emerged from the brewers’ caves in Bavaria around 5 centuries ago. The environment of a fermentation vessel is a rich one for the growth and development of yeast. Pure strains regularly mutate into wilder strains. Brewers can reuse the same batch of yeast but only a few times before it becomes something different altogether. So, the idea that lager yeast could have mutated in the cool caves of southern Germany didn’t really seem all that far fetched, at least to me it didn’t.
But, researchers in the field of teeny-tiny living things, knew better. It has been clear to them for quite some time that lager yeast wasn’t just a mutation of ale yeast. It was a hybrid of ale yeast and some wild yeast that then mutated in the brewers’ buckets. The real mystery was where did this proto-lager yeast come from?
They started searching in Europe. Makes sense, right? The yeast wasn’t there. So, they expanded their search to the rest of the planet. Finally, they found their yeast in the beech forests of Argentina.
The beech trees down there drop these sugar-filled lumps of tree called galls on the forest floor. A native yeast strain there loves to eat gall sugar – sounds delightful, doesn’t it? There is so much sugar to be had and the yeast so active, that these forests reportedly smell like ethanol. Genetic testing shows that this particular strain of yeast is the missing link.
So, somehow a bit of yeast made its way from the forest floors of Argentina to the brewing vats of Bavaria where it paired up with ale yeast. This turned into the yeast that today makes the vast majority of the beer drunk in the world today. Fascinating stuff, right?