Now that we have covered two other aspects of beer, let’s move to more uncharted territory. Grains and water were more available in the ancient world. Water could be found and grains could be grown. What about yeast? In the previous blog I intimated how yeast worked. To review, yeast in tandem with oxygen eats sugars and expels CO2. The byproduct of the process (besides the expelling of gas, which becomes carbonation in a closed container) is ethanol. However, yeast wasn’t available to the ancient person. Early on in the history of beer the brewer counted on wild yeast to ferment the product. Wild yeasts in the air would happen upon the beer and create the sparks that fermented beer. Things didn’t remain thus.

Some ancients found that saliva could also produce a mold culture, which in turn, created the necessary conditions for alcohol production. Other ancients “seeded” their brew by incorporating previous brews into their current one. There happened to be enough yeast in the former brew to ferment the next. Some modern breweries are still using strains of yeast that have “seeded” others centuries ago. Even more amazingly, some styles of beer rely on the spontaneous fermentation of the ancients. Most notably, this is true of the the style known as a Lambic.

No matter what the method, yeast is extremely important to the brewing process (beer is not made without it). Though modern brewing methods have evolved, the essential ingredient of yeast for beer has not changed. No matter how refined and various the conditions have become, yeast is still the simple truth that makes beer possible. In the next installment of the yeast discussion, I will talk about what different yeasts do. It is my hope that this is helpful for beer education.