What’s the Difference Between Ales and Lagers?

By David Nilsen

There are a lot of misconceptions about the difference between ales and lagers, the two major categories of beer. Thanks to mass-produced brands passing off bland, watery beers as the highest level of lager brewing, the average consumer thinks “lager” is code for “flavorless.” The truth is, lagers can be brewed with all the character and quality of ales. Just ask anyone from Germany, where lagers are revered (and where many of our craft lager styles originated).

Lagers aren’t necessarily weaker or milder beers than ales, and they certainly aren’t easier to brew. In fact, they typically take longer and cost more to make than ales.

The difference between lager and ale comes down to just two behind-the-scenes brewing details: yeast and temperature.

While sour beers that use wild yeast and bacteria have become popular in recent years, the vast majority of beers are brewed with one of two species of yeast: Saccharomyces cerevisiae for ales, and Saccharomyces pastorianus for lagers. S. cerevisiae is the same species used most commonly for bread baking, and it’s also one of the primary microorganisms involved in fermenting wet cacao before the chocolate-making process (in fact, cacao has been fermented using yeast from ale brewing, and vice versa). 

Both species consume sugar and turn it into carbon dioxide and ethanol (alcohol), but ale yeast prefers to work at a higher brewing temperature than lager yeast. The lower temperature for lager means the yeast produces fewer aroma and flavor compounds, leading to a smooth, clean taste. Additionally, lager brewers condition their beers for weeks or even months at very low temperatures after fermentation to further refine the beer’s profile, whereas ales tend to condition for a shorter period of time.

From a sensory standpoint, this means there are fewer yeast-derived aromas and flavors in lagers than in ales. Many ale yeast strains produce varying levels of esters (usually fruity) and phenols (usually spicy). Many ales are prized for these flavors, such as the banana and clove notes of German wheat ales, the fruity and spicy character of Belgian ales, or the subtle fruitiness and earthiness of many British ales. Lagers, however, are all about clean, refined, classy profiles in which beauty is found in the interplay between malt and hops. Lager yeast does its work without leaving much trace of itself behind.

Beyond that, lagers can be every bit as characterful as ales, so if you hear “lager” and think “boring,” think again. That toasty, malty Oktoberfest you enjoyed this fall? Lager. The big, boozy doppelbock you’ll have this spring with its decadent chocolate and dried fruit aromas? Lager. Rauchbier, with its smoky, bacon-like flavor? Lager. If you love hoppy beers, some craft brewers are even brewing IPLs—India Pale Lagers—that combine the crisp profile of a lager with the hop aromas and bitterness of an IPA.

There are dozens of styles of both ale and lager, and they can be very different from each other within each category. In fact, many ales might have more in common with some lagers than with other ales.

The next time someone makes up some other reason for the difference between ale and lager, remember: it’s just yeast and temperature!