It’s time to get a little funky and discuss one of the least thought of components of beer. It’s time to talk about yeast.
You’re probably not going to like what you hear. Yeast is, literally, everywhere. It’s on the skin of your fruit. Heck, it’s on your skin! It’s in your digestive track. It’s blowing around in the air surrounding you right now. Yeast primarily reproduces asexually by budding, so as long as the temperatures are right there is no stopping its growth.
The two primary yeast strains used in beer making are Saccharomyces cerevisiae (top-fermenting ale yeast) and S. pastorianus (bottom-fermenting lager yeast). Both strains gobble up the carbohydrates malted grain provides and, uh, for lack of a nicer way to say it, excretes carbon dioxide (the bubbles in your brew) and alcohol (the real reason you’re drinking this stuff).
Then there are the Belgian strains of yeast. Brettanomyces has at least 5 different species, each causing different scents, flavors and textures. “Brett,” as it’s known in beer circles, is thoroughly distinctive in what it does to beer, so much so that many commercial breweries won’t even go near Belgian yeast in case it alters their product. No one wants their porter to go sour or their pilsner to smell like horse blankets.
Brett, like all yeast, gets its microscopic hooks into every single nook and cranny available in a brewery and propagates eternally unless killed off by chemical means. This requires some serious bleach-spraying (messy) and hardcore HEPA filters on the A/C units (expensive).
Yeast even gets in the brewers, too. A couple of years back, Rogue Ales brew master John Maier discovered a unique strain of yeast growing on his face. His constant companion since joining Rogue in 1989, his beard had picked up various yeasts that, by 2013 at least, had morphed into a new species. So, following their “grow your own” motto and farm practice, they isolated this yeast and had it cultivated in a laboratory… lest you think he’s dunking his entire face into each batch of beer.
Not only was a new species discovered, a new beer style was born. Wild Ale is the classification for beer made using yeast indigenous to North America. Rogue Beard Beer (well, what else are you going to call it?) is such a brew. Very Belgian pale ale in style, Beard Beer has a nice gold color with a very fluffy head. There’s a distinct Brett sour funk at the front of the nose – almost lactobacillus-like – with peach and flowers rounding out the scents. Sweet and sour play off each other on the palate with flavors of honey, grapes, hay, Valencia orange and banana.
Like Johnny Cash, yeast has been everywhere, man. Sometimes it’s even right under your nose.