Understanding the Differences
The difference between ales and lagers technically comes down to the yeast used. And since we’re getting technical, the actual type of yeast used most commonly for ales is Saccharomyces cerevisiae.
When ale yeast is pitched into the wort, it’s left to ferment between 65 and 75 °F—generally speaking, the warmer the wort, the faster the yeast ferments.
During the primary fermentation, when the majority of sugars suspended in the wort are consumed by the yeast and converted to ethanol and carbon dioxide, the layer of yeast sits on top of the liquid and slowly begins to fall to the bottom as the sugars are consumed. This process is called flocculation.
The two main points here are where ale yeast sit during fermentation (on top of the wort), and the temperature at which they are left to ferment (between 65 and 75 °F).
Some common styles of ales include the following:
As you may have guessed, the two criteria that make an ale an ale also make a lager a lager! The yeast most often used to create lagers, Saccharomyces pastorianus, is closely related to the yeast used to make ales, but there are a few key differences.
While ales are fermented between 65 and 75 °F, lagers are fermented in much colder temperatures between 45 and 55 °F.
Fun fact: “lager” means “warehouse” in German, and lagers, originating in Germany, were fermented in colder warehouses or storehouses that naturally stayed in this temperature range.
Additionally, while the yeast in an ale sticks to the top of the wort during fermentation, the yeast in a lager sit at the bottom of the fermentation chamber throughout the primary fermentation.
Some common styles of lagers include the following:
While the fermenting temperature and the level at which the yeast sit to ferment are the main differences, there are a few others.
Because the beers are brewed at very different temperatures, the time it takes for the fermentation to be completed varies as well. Yeast generally works faster in warmer temperatures, and since ales are brewed in warmer fermentation chambers, the primary fermentation finishes in about 1-2 weeks, which is 2 to 3 weeks faster than it takes a lager to go through primary fermentation.
Ale yeasts also produce more esters and phenols, which tend to give beer interesting flavors, not characteristic of the malts or hops going into them. These generally taste fruity or spicy. Lager yeasts create a “cleaner” taste, so you tend to experience more of the malt flavor nuances.
And there you have it! With the seemingly countless number of styles of beer available everywhere, it can get pretty confusing deciphering the differences. Starting at the top with the differences between ales and lagers should help to grasp the styles a bit more. Now get out there and try to see if you can taste the difference!
Ales and lagers differ mainly in the yeast and the fermentation temperature. Ales use Saccharomyces cerevisiae, which sits on top of the wort and ferments between 65 and 75°F. Lagers use Saccharomyces pastorianus, which sits at the bottom and ferments much colder, between 45 and 55°F.
They describe where the yeast sits during primary fermentation. Ale yeast is top-fermenting: it forms a layer on top of the wort and slowly drops to the bottom as the sugars are used up. Lager yeast is bottom-fermenting and stays at the bottom of the fermenter the whole time.
Yeast works faster in warmer temperatures, and lagers ferment at 45–55°F, compared with 65–75°F for ales. Ale primary fermentation usually finishes in about 1–2 weeks. A lager’s primary fermentation takes 2 to 3 weeks longer than that.
Ale yeast produces more esters and phenols, which give the beer fruity or spicy flavors that don’t come from the malt or hops. Lager yeast makes a cleaner-tasting beer, so more of the malt character comes through.
Lagers ferment cooler and for longer, which gives yeast and other particles more time to settle to the bottom. The result is a clearer, cleaner beer.
Common ales include pale ales, IPAs, stouts, porters, brown ales, and saisons. Common lagers include German Pilsner, Vienna Lager, American Lager, and Bock.
