Flavor Fever: Exploring Lager’s Outer Limits

Lager is made at the cellular level—and at the cultural one. How far can you push lager—with different ingredients, fermentations, sensory profiles—until it becomes something else? Randy Mosher ponders the science, the traditions, and the pragmatism.

Randy Mosher Aug 24, 2021 - 10 min read

Flavor Fever: Exploring Lager’s Outer Limits Primary Image

Photo: Matt Graves/

In the early days of American microbrewing and homebrewing, when our modern beer culture was a shiny new thing, experts often divided the world into lagers on one side and ales on the other. Some would even compare lagers to white wines and ales to reds. The idea was that ales were bolder, stronger, and more bitter than lagers. Assuming that “lager” meant only pale, pilsner-like beers, maybe there was some logic to it.

But in terms of chemical reality, the difference is that lager’s cooler fermentations produce fewer chemical by-products. These can be smallish molecules called esters; heavier, even oily alcohols called fusels; and others.

I like to think of yeast cells as leaky bags of goo. Inside, multiple chemical processes are occurring—absorbed sugar is being snipped apart, and carbon energy units are popping off to fuel cellular activity. Excess energy is stored as fat. Waste is sequestered or expelled. Amino acids assemble into proteins. Sometimes, the cell is making baby yeast. Each process is a sequence of molecular transformations with multiple chemical actors. Some have potent aromas, and those can leak out into the beer.

All of these reactions speed up as temperature rises. For any given yeast strain, the warmer the fermentation, the more rapid the reactions. Accelerated chemical activity means more of these intermediates adding their flavors to the beer. At the low temperatures of lager, there is less activity, and the yeast is able to keep the chemistry cleaned up as it goes.


Whatever the yeast strain—whether called an “ale” or “lager” type—the actual fermentation takes less than a week. Following that, there is a post-fermentation period called conditioning or maturation, where the “green” beer rests and clarifies, while still-active yeast removes many of these unwanted chemicals—especially the apple/grassy/raw-pumpkin smelling acetaldehyde and the hyper-buttery diacetyl. But there are limits to the maturation process, and not all of these flavor chemicals are removed. Esters and phenols generally remain in the beer.

The Sensory Problem

So, there is a clear chemical difference between ales and lagers, but can we taste it? Given the supposed chasm between these groups, you’d think it would be easy. Often, it’s not. I have judged lagers at competitions with senior-level brewing staff from major industrial beer companies; often I was awestruck by their effortless ability to run through the flight and plink the losers: “Ester ... Ester … Really estery ... Out!” I struggled to keep up, even with decades of judging experience. The effect is subtle: You’re looking for even a hint of vague fruitiness, perhaps with a pear, banana, or apple character. With practice, you can get the hang of it.

At 5 Rabbit Cervecería in Chicago, we recently changed the fermentation of our Super Pils (7.2 percent ABV, 60 IBUs) from a cold-conditioned ale to a true lager. There was a definite difference, but the beer never had been really fruity. The effect was more like lifting a veil off the malt and hops, which punched through more clearly after the change.

The real-world situation is far more complex than the Beer 101 shorthand of ale versus lager. For most, the global lager standard is mass-produced adjunct beers, fermented at warmer temperatures and aged for shorter periods than traditional versions. This means they retain a wisp of ale character: In Coors, for example, there’s a little banana candy; Budweiser has a bright apple note. There are also lagered ales (obergärige lagerbier) in the form of Kölsch and Düsseldorfer altbier, which use unique yeast and combine an ale fermentation with cold conditioning—another kind of hybrid. Steam beer further muddies the waters.


The Cultural Perspective

For most people, from a sensory standpoint, the difference between identical recipes brewed with different fermentation regimes is subtle at best. Culturally, though, they are different worlds.

Every beer style has a point of origin and a web of traditions surrounding it. This shows itself in ingredients, recipes, yeast strains, strengths, colors, seasonality, and more. Every culture loves its beers, but in Bavaria, where lager originated, it is embraced with near-religious fervor.

Being a somewhat organized people, Bavarians put strict rules in place regarding their beer—the most famous of all beer edicts, the Reinheitsgebot. From a style point of view, the main thing it stipulated was that beer—chiefly, lager—must be brewed from only malt, hops, and water, but it allowed for the use of wheat and more in ales. However, at least equal in impact to the Reinheitsgebot was the Bavarian reverence for tradition. This is a region where people still wear leather pants. In brewing, that meant that innovations were behind the scenes until dramatic changes to kilning technology and increasing scale triggered the development of amber (Vienna) and pale (pilsner) lagers in the mid-19th century. The whole gamut of styles remains today, even if the darker styles are underloved.

As homebrewing and craft enterprises got going in the United States back in the 1970s and ’80s, brewers naturally looked to classic European styles as models. The English ales were inspirational, probably because they were anti-lagers—a blank slate for the kind of experimentation that was blossoming. Back then, there wasn’t much English ale in the Americas, so brewers had to rely on written descriptions or pub-fogged travel memories. So the standard of authenticity was low, or even unimportant to brewers trying to find a new way forward.


Craft lagers came later. The new “weird hops and crystal malt” paradigm for ales didn’t fit, and eventually the market was ready for something crafty that was also traditional. As brewers threaded that needle, there was that giant Reinheitsgebot anvil dangling above everybody’s heads, enforcing even the unspoken rules of tradition. Fast-forward to today, and not that much has changed. Most craft-brewed lagers still stick to traditional models.

There’s nothing wrong with that, but here is a worthwhile question: How far can you push the boundaries of lager styles and not puncture the illusion of lager-hood?

Exploring the Limits

Lager gravity and alcohol are pretty flexible, up to a point. While the classicists at the Weihenstephan brewing school near Munich decree 11.8°P (OG 1.048, resulting in about 5 percent ABV) as the optimum gravity for pils, shooting for 9.5–10°P (1.038–1.040) will get you an all-day drinker in the 4-point-something ABV range. Or you can even jump to 14.5–15.5°P (1.059–1.063) and still not blow your cover. Go much higher, and you may land in maibock or even imperial pils territory.

Polish breweries routinely make pale lagers all the way up to malt-liquor range at 9 percent ABV, although those can have a bit of rocket-fuel flavor. A trick for these is to use the palest possible malts, which often have pleasantly grassy aromas.


Bocks are pretty flexible, since the style familiarity is low. Pale versions (such as maibock) can have a fair load of hops and even be a little IPA-like if you push the boundaries. Lagunitas founder Tony Magee once told me that he designed their pils (6 percent ABV, 35 IBUs) to “have the intensity of an IPA, but with that lager character.”

Then there are hops. A few German and Bohemian landrace hops have been crowned as “Noble”: Saaz, Tettnang, Spalt, and Hallertau Mittelfrüh. They’re lovely, but as raw material for worldwide breeding programs, there are dozens of variations on their themes. We use German Saphir and Slovenian Celeia in the aforementioned Super Pils, producing a Euro-type lager with bolder, more assertive character. Many U.S. varieties can fill that role: Crystal, Loral, Mt. Hood, Talus, and Ultra, to name a few.

Hops with distinct floral or fruity characters make for subtle, characterful variations: Mandarina Bavaria, Hüll Melon, and the French-grown, strawberry-tinged Barbe Rouge come to mind. Southern Hemisphere hops, many of which have Noble parentage, can be lovely. I’ve used the lemon-lime notes of Motueka to brighten up a blonde ale, but they would be equally at home in a pils. There are others sneaky enough to pull off a near-classic lager, if used with some restraint: Pacifica, Riwaka, and Nelson Sauvin.

We’ve recently seen the arrival of so-called “cold IPAs,” which their advocates insist are definitely not imperial IPAs or IPLs; it’s a fine distinction. No matter how you define them, they are clearly a hybrid style, sometimes using neutral rice or corn adjuncts to lighten their bodies. Others are using Norwegian kveik, particularly Omega’s Lutra strain, which makes a clean, lager-like beer very quickly.

You can even incorporate botanicals if you use a light hand. I particularly like florals: fruity elderflower and chamomile, peachy osmanthus, and violet-like orris root are nice. If you’re really careful, even sexy jasmine and shapeshifting lavender can be wonderful.

In your explorations, though, you just have to keep one foot firmly planted in the tradition, lest you wander off into the wilderness.