One of my favorite facets of beer is the fermentation process. Nothing harkens to the productivity and preparedness of humans like their ability to preserve fresh food for later. Fermentation is one of the many ways homesteaders of the past (and present, with the addition of the automobile and market as a back up) preserved summer and fall’s bounty for the long winter.
Unlike other methods of preservation, such as canning or drying, fermenting actually changes the original ingredients into something chemically different. So what’s going on during fermentation?
Fermentation is essentially the process of turning carbohydrates into alcohol, acid, or gas— the handiwork of various microorganisms, and in beer’s case, yeasts. When brewing beer, fermentation is a metabolic process in which the yeasts are consuming the sugars in the wort from the malt, turning them into alcohol and carbon dioxide (hello, tiny bubbles!).
At what temperature and for how long the beer is stored depends on the type of beer being fermented. These types are most notably ales and lagers. The difference lies in the yeast.
Ale yeast strains are called Saccharomyces cerevisiae, or top-fermenters, and they require warmer temperatures for shorter periods of time to ferment. These yeast strains make ales higher in esters. Saccharomyces uvarum are bottom fermenting yeast strains that make lagers. They ferment in lower temperatures and for a longer period of time. The colder fermentation gives lagers a more clean taste.
As a new beer hits your taste buds and you analyze its flavors and aromas, generally you’re thinking about the malt and the hops. Personally, I think yeast is the real star here. Without it, what you know as beer would just be grainy-mash water.
Do you play around with fermentation? Got some home-brew in the cellar, kimchi in the crock?