Craft breweries favor the ales with the proliferation of IPAs, Stouts, Sours, and Barrel-Aged brews out there. But when considering the global beer scene, it’s the Lager style that’s dominant. To the layman, who can only picture Budweiser or Corona, the Lager must seem like a humble brew. An effervescent but flavorless bore. But there really is so much more to lagers than that.

This article will examine the Lager’s history, how it’s made, and the versatility in its styles.

The Difference Between Ales and Lagers

To put it simply, the primary difference between ales and lagers is that ales ferment at around room temperature (or warmer) and lagers are fermented and conditioned when cold.

The process called “lagering” used to take place over several months in cold spaces like cellars or even caves. Only in recent history has improved technology allowed to reduce the production time to a little less than a month. Even so, that’s still quite a bit longer than the three to ten days it takes for an ale to ferment. So why did anyone bother with the lagering beers at all? The answer dates back to the 16th century.

A Brief History of the Lager

Perhaps you’re already familiar with the Reinheitsgebot, the beer Purity Law that dates back to 1516 in the Bavarian region of Germany. For those not so familiar, there was meeting of nobles in the city of Ingolstadt. It was there that Wilhelm IV, Duke of Bavaria, famously proclaimed that all Bavarian brewers could only include barley malt, hops, and water in their beer. Incidentally, yeast was only added later, upon its discovery.

The Purity Law was a culmination of nearly four centuries of work to improve the quality of beer in the realm. Wilhelm may get the credit, but in reality, there had been similar laws enacted in various towns previously.

But this isn’t that law which introduced the world to the lager.

A few decades later, Wilhelm’s son and successor, Albrecht V, issued a decree that may not be as well known, but it profoundly changed the world of beer. Albrecht restricted brewers to only produce beers during the seven months between Michaelmas and the Feast of St. George.

Based on empirical observations, it was decided that the colder months between September 29th until April 23rd was the best time to brew beer. That is, instead of brewing beer during the summer.

And it was with that ruling, that an otherwise minor figure in world history influenced most of what is brewed today.

Little Known Law Leads to Global Dominance

So how did this 16th century law lead to the worldwide proliferation of lagers? As stated earlier, it’s the yeast strain that makes the lager differ from the ale.

Today, it’s understood that spoiling bacteria becomes more active at warmer temperatures. And that bacteria tends to go dormant when cold. But the brewers of the Old World didn’t understand the biology of fermentation. What they knew was that ales brewed in warmer months tend to spoil from bacteria while the lager yeast strains were resistant. The brewers didn’t know why but they did know they preferred to lager their beers instead.

And over the centuries, it was the Lager that took over the world.

The Yeast Strains

Ale yeasts and lager yeasts are different species altogether. The ale yeast is Saccharomyces cerevisiae while the lager yeast is Saccharomyces pastorianus (sometimes described as Saccharomyces carlsbergensis or Saccharomyces uvarum in older texts).

The ale yeast Saccharomyces cerevisiae generally thrives at temperatures above 60°F (16°C). Ale brewing is within the reach of most homebrewers because optimal temperatures for ale fermentation happen to be around room temperature. And so no extra equipment is needed.

Saccharomyces pastorianus, on the other hand, prefers the cold. Lager strains can ferment down into the mid- to low-40s Fahrenheit (single digits Celsius) and can metabolize the sugar melibiose (a disaccharide sugar that Saccharomyces cerevisiae can’t break down).

Lagering a Beer

So now you know that brewers over time chose to lager their beers instead of making ales. And that the lager yeast strains ferment at low temperatures. But after fermentation, the process calls for an extended period of cold conditioning. Better known as lagering, the brew is kept at temperatures near freezing.

During that lagering phase the yeast cleans up any off-putting flavors while round out the beer’s palate. The prolonged yeast activity breaks down certain fermentation by-products that would have been off-gassed in an ale fermentation, but remain in solution at lager temperatures.

Pale lagers such as the Pilsner and Helles may require only four weeks of lagering, while Doppelbocks may need six months or more. Anheuser-Busch famously conditions its flagship beers on beechwood chips. Beechwood is itself neutral in flavor (especially after having been boiled), but the chips do supply additional surface area, keeping lager yeast in contact with the beer during the conditioning phase.

The Various Styles

Most people might equate a lager to a Bud Light or a Heineken, and yes, most of the lagers found around the world are pale lagers often found in green or clear bottles. But like ales, lagers have numerous styles of varying character.

The flavor differentiator of the lager yeast, though, is that cold temperatures suppress the fruity esters and spicy phenols that the ale yeasts produce. And thus, a well-made lager almost exclusively showcases its malt and hops, with only subtle fermentation character provided from the chosen yeast strain. It’s possible to detect a bit of sulfur or some green apple but that’s about it.

That being said, there’s a lot of variety to be found in the lagered brews.

To begin, there’s lighter fare like the Pilsner, Helles, Festbier, and Kölsch (which begins warmly-fermented and is cold lagered later).

There are hoppy lagers like the IPL and more flavorful ones like the Vienna Lager, Dortmunder, and Märzen.

And then there are the most expressive of the bunch; the darker European styles like the Altbier, Schwarzbier, Munich Dunkel, Bock, Doppelbock, Eisbock, and Baltic Porter. And there are even variations within those styles.

Hopefully this article helps you appreciate the lager beer style a little more.