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Ask Kate About Beer: What's Kellerbier?

At the Firestone Walker Invitational Beer Festival held in Paso Robles, California, earlier this month, the temperature was a bordering-on-hot 80 degrees. Festival attendees painted on sunscreen or huddled under shade, and I even saw a small line for, of all things, the water fountains. But brewers in attendance had anticipated the summer heat, bringing plenty of lagers in addition to their smoothie-flavored IPAs and barrel-aged stouts. Among the lagers, I noticed a solid crop of them labeled kellerbier or keller pils, more than I had the year prior. So, what are they?

The answer certainly depends on context. Kellerbiers are, you guessed it, of German origin, specifically from the southern region called Franconia. Keller just means "cellar," and referred to the underground storage caves where, prior to refrigeration, townspeople kept their beer cool. You can still visit some of these kellers, which are definitely on my travel bucket list.

Joe Stange, the Berlin-based co-author of Good Beer Guide Belgium and a frequent traveler to Franconia, tells me he located the term kellerbier in a German dictionary printed in 1805. The definition specified the beer was not just beer obtained from a person's own cellar, but from the communal, public keller.

"Especially in Franconia, that was where and still is where you go to get fresh beer. Even now there, the word is interchangeable with beer garden," he says. "Today there are some breweries, if you get their beer in a bottle, they'd call it helles or lager beer, but if you go to their keller, the same beer is called kellerbier."

This brings us to perhaps the most important thing to know about kellerbier: It is not a style the way a porter or a pale ale is, but a method of making and serving beer. (The term keller bier is also sometimes used to refer to lager served directly out of its brewing vessel.)

"Kellerbier is maybe like the German version of saison, where it's not so much of a style but a story," Stange says.

It's a broad, umbrella term under which many specific styles of beer can fall. Keller biers can be sweet or bitter, light or dark or even smokey. Framingham, Massachusetts-based, lager-focused brewery Jack's Abby has an entire line of kellerbiers, of which it will brew about a dozen different styles this year.

He says that in Germany there's just one requirement to label a beer kellerbier, and it's that the beer be unfiltered. Much of the beer consumed around the world is filtered to remove tiny particles left over from the brewing process. But more rustic, traditional styles like kellerbier often forgo filtration, which gives the beer a lightly hazy appearance.

"Outside Franconia, kellerbier has come to mean shorthand for unfiltered lager," Stange says. "I think maybe in the U.S. craft scene, it has become shorthand for unfiltered, like it has in Germany. It identifies with some German influence or inspiration and it sounds cool."

If you take away only one message from this story, it's that in terms of the beers you'll encounter in the U.S., keller bier is unfiltered lager.

"The first thing I try to point out when I do training is: Kellerbier is not a style," says Jack's Abby co-owner and brewer Jack Hendler. "It's like lager or ale, a broad category. For us, it's a way to talk about some of the unique ways we're brewing beer as opposed to a specific style."

So, kellerbiers are unfiltered lagers. But more than that, Hendler says, they're a way to explore traditional brewing methods like using open fermentation, natural fermentation, or specialty ingredients. Jack's Abby's next beer in its keller bier series will be a lager brewed with spelt.

"We found a great interest in keller biers in general. I don't know think consumers necessarily know what kellerbier means, but there's an authenticity that they associate with the name and appreciate," Hendler says.

Hendler is fortunate to travel to Germany, where each year he and his team select ingredients—and drink beer. Both he and Stange emphasize that American brewers shouldn't slap kellerbier on labels without thinking through what it means to them and what aspects of their brewing are in line with the traditional, unfiltered beers of Germany.

"If a brewer is going to use that word, I know not everyone can go have a holiday in Franconia, but I would highly recommend it," Stange says. "If not, then at least you should be evoking that feeling of people sitting under the chestnuts and drinking from a steinkrug on a sunny day."

As my experience at Firestone Walker's festival attests, American drinkers are more than happy to carry on drinking delicious, unfiltered lagers in the shade.