When it comes to beer, there are two main types: ale and lager. While both are brewed with hops, the difference lies in the yeast used in the fermentation process. Ale yeasts prefer warmer temperatures (about 60-75℉) and are considered “top fermenting”, while lager yeasts prefer cooler temperatures (about 42-55℉) and are considered “bottom fermenters”. The word lager comes from the German word meaning “store”, as lagers were first stored in cold caves to mature.
Lagers are the most consumed beers in the world, although historically they are younger than their ale counterparts. Today there are hundreds of known strains of ale and lager yeasts, and brewers can select them as if they were selecting a certain type of grain or hops. Examples of popular lagers include American Light Lager (Coors Light), International Pale Lager (Heineken), Octoberfest or Marzen (Samuel Adams Octoberfest), Bock (Einbecker Ur-Bock Dunkel), and Baltic Porter (Jack's Abby Framinghammer). Popular ales include Blond Ale (Victory Summer Love), Pale Ale (Sierra Nevada Pale Ale), India Pale Ale, IPA (Head of dogfish (60 minutes)), American Wheat beer (Three Floyd's Gumballhead), Hefeweizen (Weihenstephaner Hefeweissbier), Porter (Great Lakes Edmund Fitzgerald), and Barleywine (Stone Brewing Old Guardian).
Simply put, lager beers are brewed with bottom-fermented yeast strains that are kept at cooler temperatures (around 40-52°F), while ales are brewed with a top-fermented yeast that works at warmer temperatures (around 55-77°F, usually). Although hops are present in almost every style of beer, it tends to be in different amounts in an ale compared to a lager beer. In the cold treatment process of a lager beer, the finer flavors of hops can come out, providing a more delicate flavor without sacrificing the additions that hops can make to the finished beer. Ale yeasts can survive in high alcohol concentrations, therefore, the resulting beer has a higher alcohol content.
Lager yeast, more fragile and slower, cannot survive in environments with a high alcohol content, which makes lager beers have a total alcohol content. The Patagonian species is what gives lager yeast its interesting cold-tolerant and sulfite-metabolizing characteristics, characteristics that are manifested in the distinctive flavor and character of lager beer. There are blond beers that are as pale as classic Czech pilsners (a lager), and smooth and dark lagers like schwarzbiers that are as opaque and black as stouts (an ale). Although the differences between ale and lager beer are many, having a better idea of the facets of the brewing process and the ingredients that affect the final product allows you to better appreciate the differences between the two varieties. Lager yeast traditionally requires a little more time to brew than ale beer. The most obvious difference is that lager yeast works best in cold temperatures, temperatures that would cause an ale yeast to remain inactive.
This stage allowed more yeast, protein and hops to be deposited outside the lager, dramatically improving clarity and reducing the cold haze, which forms when a beer that has not undergone the cold treatment phase is cooled for the first time and the extra solids in the beer begin to cause the effect of turbidity. And while few of us would intentionally omit the cold conditioning phase of a lager beer, I can tell from personal experience due to equipment limitations that, as long as the primary fermentation is carried out cold, a period of a few weeks or months at room temperature can still turn out to be beer satisfying with characteristics of soft lager. Some lager yeasts work well in relatively warm temperatures, and some ale yeasts feel comfortable with conditions that would cause other strains to simply give up and flocculate.