What is the difference between ale and lager?

At first, I was going to attack this blog with the assumption that all readers would enter well-equipped with prior knowledge. Yet, considering that my aim is to help the average person become a true appreciator of beer, this supposition may hurt my goals.

Before we can begin any in-depth discussion of beer, there are some terms (jargon perhaps?) that needs to be cleared up.

Most have heard the words, “beer”, “ale”, or “lager” when describing their beverages, but the actual meaning of theses words is not always common knowledge. Everyone knows that beer is...well beer. 

But what exactly is beer? I can say that after years of being an enthusiast, I've tasted beers that I could have swore were wines. In Nepal, I had a beer that was just a big jug of grain slurry, to which boiling water was added, then sipped with a crimped straw to filter out the solid material. Then there's chicha, the South American beer where corn is chewed and spit into a bowl and dried.

Then there's the whole ale and lager conundrum. Many address the question by simply saying, “well, ale is beer made from top-fermenting ale yeast and lager is beer made from bottom-fermenting lager yeast. Duh!” But what is even meant by “top or bottom-fermenting” or just “fermenting” for that matter? Plus, this definition is problematic in that is doesn't really describe the beer itself very well.

Um, yeah, of course I know what fermentation is...it's like how beer is made.

It's actually more than that. 

All alcoholic beverages and much of food we eat—wine, beer, vodka, jagermeister, kimchi, sauer kraut, vinegar, yogurt, and even cheese—are the byproducts of a process called fermentation. It is a non-fancy word for a complex process that I don't dare describe with any depth (high school biology was a LONG time ago). Simply put, many microorganisms (namely some bacteria and yeasts) get their energy (or ATP for those who actually remember biology class) in the absence of oxygen (this is an “anaerobic” process) , by “eating” sugars and “pooping” out carbon dioxide, alcohol, and/or acids. It is what makes bread rise (have you ever noticed that if you let rising dough sit too long, it smells sour or alcoholic?) It is the same thing that makes your muscles sore after you work out (this is not to imply that if you jab a straw into your chest after some bench presses, you'll secrete beer).

Wine is yeast-fermented fruit juice. Sauerkraut is bacteria-fermented cabbage. Vodka is distilled, yeast-fermented whatever-you-got-going-bad-in-your-cellar-juice (distillation will not be addressed here). Beer is simply a yeast-fermented grain beverage. For this reason, beer is often called “liquid bread”. So that means that even saki is beer, not wine.

Wow, you used all that space just to define, “beer”?

I've barely even started, buddy.

In English, the term beer used to be much more specific. Despite being one of the first food products ever created by man (Some postulate that the discovery of brewing and baking was responsible for the creation of civilization, anchoring people to the land through agriculture instead of hunting and gathering. The oldest evidence of beer is a 6000 years old tablet from Sumeria. Think about that the next time you drink a pint.), the word beer is relatively new. By the middle-ages, beer was a northern-Europe thing, the drink of the vikings, who spread it across the continent, especially to England. As with most conquerers, their word for the beverage, øl, (which is what nordic people still call it) became the standard term. You may notice that despite the weird letter, it looks a lot like “ale”.

After hops became a common addition to European ales in 1500 and 1600's, they began to gain popularity in England. The word beer (which was what the Germans, French, and Italians called the beverage) was used to differentiate this continental-style hopped “beer” from more traditional unhopped “ale” of Britain. Even up to the 20^th century, ale and beer were listed as different drinks (as was porter, which was dark beer.).

Um...Is there a point to all this history and science? Jeesh, I feel like I'm in school again!

Well, yes there is, Mr. Boldfaced, fourth-wall-shattering-commentary.

Nearly every “beer” or “ale” contains hops, so the old meanings of these words are a bit antiquated.

Sadly, I had little success in my research tracing the way in which “ale” adopted its current meaning, but there is little argument that it means “top-fermented” beer.

Oh no...Is there going to be another science lesson?

Yes, there is. And more history too!

The vast majority of beer is fermented from one of two yeast species, Saccharomyces cerevisiae and Saccharomyces pastorianus (or simply put, ale yeast and lager yeast). There are other yeasts that people use to make beer, but it is beyond the scope of this entry.

S. cerevisiae is probably one of the most important living organisms for mankind. It is a microscopic fungus that is used to make many things, namely bread, beer, and wine. Bakers yeast, brewers yeast. They're both names for this hardy fungus. Though, up until Louis Pasteur's revolutionary 1876 book Etudes sur la Biere, fermentation was a mystery, often with religious connotations. It was common for the the same stick to be used to stir every batch of beer as “good luck”. Sometimes these sticks would be handed down for generations. These stick were covered in S.cervisiae yeast, which was transferred into each batch of beer. In reality, there were likely a variety of yeast strains, but selective “breeding” by disposing of bad sticks, eventually led to the domination of “ale” yeast in beers (note, I have no research to back this sentence.) The vikings always gave a toast to a god or a hero for each drink they took of beer. To not, would offend the gods and they wouldn't be blessed with good beer. Many Norwegian brewers still “kauke” (scream) to the gods when adding yeast to their beers.

This is not to say that there was no understanding of science in brewing. It was a well-accepted fact that beer brewed in the summer was more likely to go bad; people just didn't understand why. In 1553, Duke Albrecht V of Bavaria banned the brewing of beer between April 23 and September 29, thus “creating” this second species of yeast (S. pastorianus). Lager yeast thrives at colder temperatures (6C to 13C ideally), whereas most ale yeast strains are inactive in these temperatures. Eventually, a new cold-loving hybrid was formed. Since these beers were stored and kept cold in Bavarian caves, often with ice blocks to decrease the temperature, they came to be known as “lager”, derived from the German verb “lagern”, meaning “to store”. (All British beers were likely to be S. cervisae, due the warmer climate. When these vastly different Bavarian beers reached their shores, it is no shocker that a different word was needed than simply “ale”. Though, “Bavarian beer” would in itself imply lager. Some have argued that is was, in fact, the Americans that are responsible for the knitting “ale” with S. cerevisiae and “lager” with S. pastorianus.)

Hey man, I just want to drink the stuff!

I know you do, and there will plenty of time for that.

Knowing the difference between the two yeast strains and the beers they create will help take much of the guesswork out of buying beer. Years ago, when buying a beer, beer was just beer. Now what everyone in America called beer is called “light lager”. There are all these other names on cans and bottles and it is getting to be as complicated as buying wine. Beer styles are worthy of a whole book (there have been many), but knowing the difference between ale and lager will roughly divide the field in half (well actually lagers comprise 90% or so of all beers sold...).

So, this brings us back to fermentation. As I've discussed, ale yeast (S. cerevisiae) is called “top-fermenting” beer because of the tendency of the yeast to form a thick film on the top of the fermenting beer. Lager yeast (S. pastorianus) is called “bottom-fermenting” because the yeast seems to sit on the bottom. Both names are a bit flawed because the yeast usually sits in suspension throughout the whole beer during fermentation, despite the strain. These factors say little about why the resulting beers taste the way they do. The true difference is fermentation temperature.

When beer is fermented at a warmer temperature, the yeast cells produce chemicals that give spicy or fruity character to beer. The colder the fermentation temperature, the more “cleanly” the yeast do their job. It is just that S. cerevisiae is most active at these flavor producing temperatures (17-23C) and S. pastorianus at “cleaner” fermentation temperatures (6-13C). Lager yeasts are also stored longer. This gives the yeast time to take up these bi-products. Plus, they can eat more sugars than ales, so they are often dryer and crisper beers as well. California common (or Steam Beer) is a lager beer made at a high temperature, so it has a fruitier, most ale-like flavor.

Basically, if you see “ale” on a bottle of beer, you can expect it to be slightly thicker in body and have a more yeasty character (which will be discussed in other entries to this blog.) Lager will express most the flavor of the other ingredients (malts and hops), because it lacks these distracting yeast flavors.

Think of the two yeast species like you would friends.  If beer is a three-way conversation between hops, malt, and yeast, ale yeast is that friend that is right in the thick of things, adding jokes, one-liners, even driving the talking at times.  Lager yeast is the one that sits back and lets the others talk, but will occasionally throw in a point that keeps the other two going. (And now you have a new game to play with your buddies.  You can start labeling people as either Saccharomyces cerevisiae or Saccharomyces pastorianus. "Oh, Trudy, you're such a cerevisiae!"  I don't think it'll take off.)

I'm a cerevisiae, but I'm drinking pastorianus.

To taste the way that yeast affects beer, try an Imperial Stout along side a Baltic Porter. These two styles are very similar, they just use different yeast. Or try an Imperial Pilsner vs. Duvel.

Of course, this long, winding post is only scratching the surface of the nuances between these two categories of beer.

Uh, thanks, that helps a lot. I think.

Sources:

https://en.wikipedia.org/wiki/Fermentation

https://en.wikipedia.org/wiki/Saccharomyces_pastorianus

https://en.wikipedia.org/wiki/Saccharomyces_cerevisiae

https://en.wikipedia.org/wiki/Louis_Pasteur

http://www.forn.no/maltol/107a.htm

Mosher, Randy. Tasting Beer. North Adams, MA: Storey Publishing, 2009.

Oliver, Garret. The Oxford Companion to Beer. New York, NY: Oxford University Press, 2012

Palmer, John. How to Brew. Boulder, CO: Brewers Publications, 2006

Tags:  Saccharomyces cervisiae Saccharomyces pastorianus ale lager fermentation temperature beer knowledge