The Difference between Ales and Lagers

So it came to my attention while watching a TV trivia show, that I will not name, there seems to be a lot of confusion when it comes to the two basic categories of beer. On this trivia show it was stated that an ale was the darker of the two categories. I love this trivia program but being the beer geek that I am the statement made me cringe. I am just happy that they knew that there is a difference between ales and lagers.

Color, alcohol content, and bitterness have no factor when a brewery decides to put their beer in the two main categories. To be able to understand the difference between the two categories you must understand the variations in brewing process of the two.

There are three main variations, the yeast that is used in the production, the temperature at which the beer is fermented at, and the time the beer is allowed to "age".

Yeast:

Ale yeast also referred to as top fermenting yeast is a type of yeast that literally rises to the top while the wort (unfermented beer) is fermenting into beer. This creates a thick slurry like foam concoction at the top of the wort referred to as krausen. Top fermenting ale yeasts are used to brew (but not limited to) pale ales, IPAs, stouts, porters, ambers, English bitters, and brown ales.

Lager yeast, also referred to as bottom fermenting yeast, reproduce at a much slower rate. Because of this there is a lot less foam production and the yeast tend to settle at the bottom thus the name. Bottom fermenting lager yeasts are used to brew (but not limited to) American light lagers (Bud, Miller, Coors), munich dunkel, vienna lager, oktoberfests/märzen, pilsners, bocks, and dortmunders.

Temperature: 

Ale yeast ferment at a much higher temperature than lager yeasts. This is a big reason why the fermentation is much more violent and produce such a large head of krausen. Temperature usually ranges from the mid 60s to as high as 75 degrees Fahrenheit. Yeast that is fermented at these higher temperatures produce more of the esthery (fruit) and phenolic (banana/clove) flavors that are typical to the ale category of beer. Breweries throughout history have been "selectively breeding" yeasts to create strains with different attributes. English bitters for example use strains that produce more esters, whereas Belgian wit yeast produce more phenolics.

Lager yeast ferments at a much lower temperature and would be the reason why it seems to be less active and produces at a slower rate. These yeasts have also been "bred" to create different attributes. Lager strains will produce a much cleaner and crisp beer without as much going on as an ale yeast. These yeast produce (generally) a beer that is geared much more toward the malt flavor in the ending product.

Time:

Since ale yeasts ferment at a higher temperature they seem to ferment and mature faster so an ale can be completed in a shorter period of time. This is not saying that a good ale does not benefit from some aging. Russian imperial stouts, barley wines, old ales, and oaked ales all see great affects with some age.

With a lager, time is a virtue. Even the term lager would suggest that. It comes from German word "lagern" which means "to store." This would refer to the lagering process where a beer is stored in a cool area for an extended period of time. This aging process is beneficial to a lager's end flavor because it smooths out the harshness that may be present. At the colder temperatures (30 to 40 degrees Fahrenheit) tannins combine with haze causing proteins and drop out over the lagering phase. The lagering process began during the middle ages where beer makers would store their beer deep in caves for months to enjoy the peak of its flavor. The German lager märzen (also known as Oktoberfest) basically translated to "Marches" is brewed in March and lagered until the Oktoberfest celebration.

To add to the confusion there is such a thing as a "hybrid beer" which is a style of beer that is produced with a strain of lager yeast that ferments well without producing a lot of the estery and phenolic flavors at an ale yeast temperature. Anchor Brewing Company's flagship beer is the most commonly known hybrid beer. These will be discussed more in depth later on down the road.