Local Yeast

My take on brewing yeasts comes from a combination of science, historical accounts and many sessions thinking about how modern brewing emerged. Plain and simple, brewing yeasts that we brewers use to transform wort into the wonderful elixir we call beer do not occur in nature. This may sound like an odd and incorrect statement. After all, if brewing yeast does not occur in nature, where did it come from originally?

Brewing yeast did originally come from nature. But the modern age of brewing is hundreds of years old and breweries have housed, guarded and cultivated yeast throughout this period. In a typical brewery fermentation there is a four-fold increase in yeast cells and each time a yeast cell divides there is a chance for mutation, just like with the reproduction of all life. Unlike animals with relatively long lives and infrequent breeding, yeast cells are veritable bunny-rabbits and the rapid divisions greatly reduce the time for significant mutations to occur. This is why the yeast used in breweries is so different from yeast found in nature.

There are beers made using wild yeasts (and bacteria), such as lambics in Belgium, but to my knowledge the state of Maryland has no real history using wild yeasts to produce beer. By the way, my brewing career began when I was a homebrewer in Maryland and this fact, of course, makes me an expert on Maryland brewing! If your friend is serious about wanting to brew beer with native yeast, I suggest taking a lesson from winemakers.

Some wines produced in the United States are still made by relying on yeast that live on the skins of grapes. Many other fruits are also covered in yeast and can be used as the source of native yeast. The white, powdery looking stuff on many fruits, such as grapes, blueberries and apples, is referred to as “bloom” and is wild yeast. Maryland does have apple orchards and wild yeasts could be cultured from the bloom on Maryland apples.

The downside to this adventure is that brewers use cultured brewing yeasts instead of wild yeasts for a variety of reasons, including consistency, attenuation, fermentation performance and, most importantly, finished beer flavor. The stuff you are able to culture from the environment is likely to produce less than stellar beer and many trials resulting in disappointment will probably occur before finding a suitable yeast strain. If your buddy has determination and is able to keep his chin up during his odyssey this could be a really fun project. On the other hand, if he has a fragile ego and doesn’t do well with failure this could scare him away from brewing forever. If it were me, I’d try to get a hold of some of the yeast used to produce the Baltimore classics National Bohemian, affectionately called Natty Boh, and National Premium.

Response by Ashton Lewis.