To earlier generations of brewers, the microscopic beings responsible for fermentation typically arrived on the scene in the form of a family’s trusty brewing stick, the dank, wooden crevasses pocking the walls of a farmhouse, or straight from thin air, carried along within the currents of cool nightly breezes. While a growing number of traditionally minded brewers in Belgium, the U.S., and further abroad still rely on wild yeasts and bacteria for their spontaneously fermented creations, people today usually encounter yeast as a pack or vial from one of the two main yeast labs, or (just as often) as that murky glop appearing unannounced from a bottle of homebrew.
Beer as we know it wouldn’t be possible without yeast.
Granted, it’s hard to be sexy when you’re only a few micrometers across.
But while there have been countless developments improving the science and art of brewing over the past few hundred years—a significantly expanded variety of hops, vast improvements to malt kilning, the invention of numerous technological doohickeys to improve quality control, etc.—the identification, isolation, and selective breeding of yeast has likely been the most formative.