Beer 101: Ale vs. Lager

At its most basic level, beer can be categorized into two types: Ale and Lager. Both are "beer," but they are very different from each other and it comes down to yeast and fermentation.

Ales have been brewed for centuries and centuries. The type of yeast that's used in ales is called top-fermenting, meaning that it sits on the top of the liquid as it ages, which doesn't take very long for ales. Generally ales are aged in a matter of a few weeks (some ales are ready to go within 7 days, even). The temperature at which these special yeasts ferment is warm, as high as 70 degrees for some ales. The type and length of fermentation produces what's called "esters," which are compounds caused by the chemical reactions going on in fermentation. They result in strong flavors that are often fruity, spicy or flowery. Esters make ales complex, with a multi-layered flavor profile. They're higher in alcohol than lagers, and should be served cool, rather than cold. Some countries even serve ales at room temperature. Types of beer that fall under the ale umbrella are Pale Ale, Amber Ale (all the "Ales," naturally), Stout, Porter, and Wheat beer, among others.

Lager comes from the German word "lagern," which means "to store." Lagers typically ferment much longer than ales do, typically for many months, and at much colder temperatures, as low as 50 degrees. Fermenting the yeast at such a low temperature results in increased sulfur production (rather than esters), but the increased length of storage allows the sulfur to integrate into the beer. As strange as it sounds, the added sulfur results in a crisper, cleaner flavor. Where ales's flavors are complex and multi-layered, lagers have one dominant flavor that comes through. Also unlike ales, lagers are best served cold, but not colder than 38F, as the lager will lose its flavor. If you see, in addition to "lager," of course, words like Pilsner, Bock, Helles or Oktoberfest, you're looking at a lager-style brew.