What's the difference between Ale (Beer) and Lager?

The primary difference between ale and lager lies in the yeast strains used and the fermentation process. These differences lead to variations in flavour, appearance, aroma and other characteristics. Here's a breakdown of the key distinctions between ale and lager:

1. Yeast Type:

• Ale: Ales are brewed using top-fermenting yeast strains, scientifically known as Saccharomyces cerevisiae. These yeasts ferment at warmer temperatures, typically between 15-22°C (60-72°F).
• Lager: Lagers, on the other hand, are made with bottom-fermenting yeast strains, specifically Saccharomyces pastorianus. These yeasts ferment at cooler temperatures, usually around 7-13°C (45-55°F).

2. Fermentation Temperature:

• Ale: The warmer fermentation temperatures of ales result in a faster and more active fermentation. This often produces more complex fruity esters and, depending on the yeast strain, spicy or phenolic flavours.
• Lager: Lagers undergo a slower, cooler fermentation process, resulting in cleaner and crisper flavours with fewer fruity esters and a smoother overall profile.

3. Fermentation Time:

• Ale: Ales typically have shorter fermentation periods, often measured in days to a few weeks.
• Lager: Lagers require longer fermentation and conditioning times, sometimes taking several weeks or even several months, which contributes to their characteristic smoothness.

4. Flavour and Aroma:

• Ale: Ales are known for their diverse range of flavours, which can include fruity, floral, spicy and robust malt notes. Many ale styles also have a more pronounced hop character.
• Lager: Lagers tend to have cleaner and crisper flavours, with a subtle malt sweetness and, in many examples, a milder hop presence. They are known for their smooth, well-balanced profiles.

5. Appearance:

• Ale: Ales can range in colour from pale gold to deep brown or almost black, and they may be cloudy or clear, depending on the style and brewing process.
• Lager: Lagers are often associated with a paler colour, ranging from straw-yellow to amber, and they are typically clear and brilliantly bright. However, darker lager styles such as dunkel, schwarzbier and bock show that lagers can be every bit as dark as ales.

6. Styles:

• Ale: Ale encompasses a wide variety of styles, including pale ales, India pale ales (IPAs), stouts, porters, milds, bitters and Belgian ales, among many others.
• Lager: Lagers include styles such as pilsners, helles, Märzen, Vienna lager, dunkel and bock, with a general focus on clean fermentation and balanced flavours.

7. Conditioning and Storage:

The word lager comes from the German word lagern, meaning “to store”. After fermentation, traditional lagers are kept at low temperatures for an extended period. This cold-conditioning stage allows yeast and other particles to settle out, while some of the rougher flavours produced during fermentation gradually soften. The result is usually a cleaner, smoother and more refined beer.

Ales can also be conditioned for long periods, particularly stronger styles such as barley wines, imperial stouts and Belgian strong ales. However, many everyday ales are ready to package or serve considerably sooner than a traditional lager.

8. Are the Differences Always Obvious?

Although ale and lager are often treated as two completely separate camps, modern brewing has blurred the boundaries. Some brewers ferment lager yeast at warmer temperatures to create faster, more expressive beers, while others ferment ale yeast unusually cool to produce a clean, lager-like character.

There are also hybrid styles, such as Kölsch and altbier, which are brewed with ale yeast but conditioned at cooler temperatures. California common beer takes almost the opposite approach, using lager yeast at temperatures warmer than would normally be expected. This means that flavour alone does not always reveal whether a beer is technically an ale or a lager.

It's important to note that within both ale and lager categories, there are numerous substyles, each with its own characteristics. The distinction between ale and lager is a foundational concept in the world of beer and serves as a starting point for understanding the enormous diversity of beer styles available.

It's interesting that many drinkers describe themselves as either an ale drinker or a lager drinker. I've met relatively few people who are truly agnostic and will happily drink whatever is available without having some sort of preference. I will nearly always fall on the side of ale unless I spot a lager I've never tried before. Even then, my favourite lagers tend to be maltier, fuller-bodied and more bitter than the standard mass-produced lagers found on most shop shelves.

That preference probably says more about flavour than fermentation. Someone who says they dislike lager may simply dislike very light international lagers, while happily enjoying a rich dunkel or a strongly hopped Czech pilsner. Equally, somebody who claims not to like ale may be surprised by a clean golden ale or Kölsch-style beer. There is far more crossover between the two families than the familiar pub question of “lager or ale?” might suggest.