All beer can be categorized as either an ale or a lager. Ales and lagers are defined by the yeast they use to ferment. Ales are fermented with Saccharomyces cerevisiae at room temperature. Ale yeast floats and ferments at the top. Lagers are fermented with Saccharomyces pastorianus at refrigerator temperatures. Lager yeast sinks and ferments at the bottom.
Most beer consumed in the world today is a lager because of its light taste and body. Most beer brewed by craft breweries are ales because of the full body and complex flavors produced. Lagers have a slower fermentation time which usually take twice as long to finish than ales. This is another reason why small craft breweries produce mostly ales.
Yeast is naturally occurring, however, brewer’s yeast has been domesticated for hundreds of years in order to effectively ferment beer into the flavors we enjoy today. Domestication of yeast works just like it does for animals such as dogs. Hundreds of years ago, wolves were selected have much more tame characteristics and bread with each other until the domesticated dog was born. With yeast, the barrel of beer that fermented the cleanest and with the most desirable flavors was then poured into the next batch of beer, effectively selecting for the most alcohol resilient yeast that thrive on consuming maltose (malted barley sugar).
Ale yeast has been used to produce beer since around 5000 BC. Lagers are relatively new to the brewing scene. They first arose in Bavarian breweries in the late 15th or early 16th century, then eventually spread to the rest of Europe (most famously to Pilsen, the birthplace of pilsner) and eventually to the rest of the world.
Recently in 2011, it was discovered that the lager yeast species is hybrid strain of the original ale yeast and a cold resistant yeast found in the forests of Patagonia. It is believed that this cold resistant strain came over to europe during the trans atlantic trades of the 15th century and bread with ale yeast to yield the hybrid strain that we know today at lager yeast.
The German word “lagern” means to store. Lagers undergo special a cold-conditioning step, but ales do not. In order to achieve a crisp, light flavor known in lagers, they are fermented cold and then aged or “lagered” at cellar temperatures. This lagering process helps clean up any impurities in the beer as well as settle out any particulates floating in the beer. Lagering leads to delicious, clear beer. Ales are fermented warm which contributes to fruity, estery, and complex flavors. Ales do not need to be aged after fermentation, however, if they are aged, it does help clean up the beer and will definitely help produce delicious beer.
Now go out and taste the difference between an ale and a lager for yourself. Let us know what you think.
-the Pubinno Team