Beware the kettle sour beer

A small battle has erupted in the craft beer world over one of the hottest styles of beers — sours.

The conflict is over how the beers are created — kettled versus aged.

The former is a trendy way to make sour-tasting beer. It is much quicker, doesn’t require any special equipment and is less expensive to make. The latter is an age-old tradition that involves careful production, long periods of fermentation and use of bacteria or wild yeast that if left unchecked can contaminate other beers. Traditionally aged sours can be expensive both to make and drink.

(This section was edited for clarification.) The relatively inexpensive kettle souring technique produces a clean, tangy beer high in acidity that can be brewed in a few weeks without the fear of contaminating the brewhouse. In quick-style souring, the beer can be soured during the mashing process when lactobacillus bacteria eats the sugars and converts them to acids to produce that sought-after pucker. It also can be soured in the boil kettle before the heat is turned up and the bacteria is killed off or pasteurized. The latter process is called kettle souring. (We are using a catch-all term of “kettle-souring” in the place of “quick souring.”)

Traditional sours often are inoculated with lactic acid bacteria (multiple strains of Pediococcus and Lactobacillus) and sometimes use Brettanomyces yeast after the boil for extra fermentation. They can then ferment up to two years until poured. To simplify it, kettled sours are infected before the boil. And traditional sours are infected after the boil.

Breweries throughout the country and in Colorado are kettle-souring beers — from Denver Beer Co. to Odd13 Brewing in Lafayette. Nationally, breweries making kettled sours include Boulevard Brewing Co. from Missouri and Breakside Brewery from Oregon, among a whole slew of others.

To purists, however, quick souring is a bastardization of a noble brew.

“There are people whose families run breweries for hundreds of years,” said Chad Yakobsen, founder of Crooked Stave Artisan Beer Project that produces world-renowned aged sours. “There is tradition to be upheld. It is important to say how beers are produced. For us to say that we produce aged-sours, it justifies the beer and production and character.”

The process is very, very different than aged-souring, Yakobsen said.

“You put them into a fermenter or oak and the natural organisms and Brettanomyces take their time to create the complex characteristics,” Yakobsen said. “The other is very one note. It is directed at the acidity. It doesn’t have the time and artistry in it. It is not my thing.”

Crooked Stave put on Wednesday night’s What the Funk Invitational — a glorious event for sour-beer lovers. Few quick-soured beers were poured because all beers at the event must be barrel-aged, Yakobsen said.

James Howat, owner and head brewer at Former Future Brewing Co. and Black Project Spontaneous & Wild Ales, is known to wear a T-shirt that says “Death to Kettle Sours.” He doesn’t mince words. He doesn’t like kettled sours. At Former Future, customers are immediately informed on the leaderboard that the sour beers are not produced through kettling.

“I don’t abide bad beer,” he said (another T-shirt slogan?)

“My main thing is a lot of brewers have seemingly suddenly decided to make sour beers and yet don’t have the ability to have the patience, investment or knowledge to make aged sour beers,” he said. “They are saying, ‘OK. Sours are popular now. We want to make a sour now.’ … And they are making a lot of bad sours.”

He acknowledges not all kettled sours are bad. But the ones that are, are putrid with major flaws, producing beers that smell like vomit or hot Dumpsters.

“Not only does the souring happen quickly, but the bad stuff can happen quickly,” he said.

He worries people who are just starting to explore sours will be immediately put off by the poorer versions.

“The public, I think, hasn’t had enough good sour beer and doesn’t understand the difference between barnyard funk of a traditional sour beer and the taste of a kettle sour,” he said. “Vomit is not a thing that should be in there.”

Traditional aged-sours can transform those bad flavors and tastes. Vomit, for example, can become a pineapple smell.

“But that doesn’t happen in two weeks.”

Brandon Boldt, head brewer at Odd13 Brewing, makes both traditional sours and kettle sours and believes there is room for both. He said you wouldn’t make a complex Oud Bruin sour with the kettling process. But a lighter Berliner Weisse works well with kettle souring, if done right, he said. The other issue is storage. Fermenting traditional sours takes up a lot of space, and smaller breweries aren’t able to hold the fooders foeders for such a process.

“To me, the main point should be to judge on product, not process,” Boldt said. “The reason we incorporate souring wort as a technique is not only a function of space or expedience, but another tool for exploration and creativity. We are synthesizing brewing techniques to try and approach new flavor and aroma combinations, which is at the heart of ‘traditional’ Belgian brewing philosophy.”

Boldt would like to end the “Death to Kettled Sours” movement and push, instead, for a “Death to Hyperbole” slogan.

“Or maybe slightly less ironic yet wordier, ‘Let’s work together to improve upon the collective quality of both soured and non-soured beers,'” he said.