Sour Beer: What You Need to Know For Your Restaurant

Beer-barrel sanitization is a thing of the past. For years, breweries have been religiously following the antibacterial mandates set forth by Louis Pasteur—but now some breweries actually welcome bacteria in their beer. Don’t believe me? Obviously you haven’t heard about the new trend of sour beer. Today’s post will get you up to speed on the methods and madnesses of the sour beer movement. 

First things first: What is sour beer?

Sour beer is a type of craft beer that ranges in taste from “acidic” to “Sour Patch Kid.” In the past, all beer was sour because of the bacteria that lurked in beer barrels in the pre-sanitization world, but once breweries cleaned up their manufacturing operations, beer began to taste like the ingredients in the beer. Since the craft beer movement took off in the early 2000s, American beers have been described as tasting hoppy, malty, boozy, chocolatey, and fruity… but now beer also tastes, er, sour-y.

What makes the beer sour? 

Sour beer gets its flavor from the yeast used to make it, and also from the deliberate introduction of bacteria to the beer.

Leery of a bacteria-filled beer? Just wait, it gets even more gross.

Typically, beer is made with “brewer’s yeast,” for which the Latin name is “Saccharomyces.” This yeast is cultured to impart a very specific flavor, the one we tend to associate with the smell of bread dough, because we also typically use this type of yeast (though a different strain of it) for baking. However, brewer’s yeast is not the only yeast available.

In fact, yeast is all around us. Literally. Yeast is everywhere. It’s in the air we breathe, it’s in the dust… it’s surrounding you right now, no matter where you are.

Bakers have known this for many years, and the artisan bread movement of a few years ago promoted local yeast collection, enabling people to sell geographically specific yeast on eBay. If you’ve ever wondered why San Francisco’s sourdough tastes better than any other sourdough, it’s because the yeast that floats around in the air there tastes really freaking good in bread.

…But let’s get back to the beer. 

Although Saccharomyces yeast has a mild, sweet taste, American craft brewers have lately decided to start using another kind of yeast, called Brettanomyces, or “Brett.” (In case you’re curious, this yeast gets into the air by floating off of the skin of wild fruit.) Brett’s Latin name means “British fungus,” because in 1904 when it was discovered by a guy named N. Hjelte Claussen, he found out that it was responsible for the spoilage of English beer. No one wanted spoiled beer, so Brett was promptly eradicated from the beer supply.

To be completely honest here, by the way, the Belgians kept making their beer with Brett because they liked the taste. When the rest of the world started importing popular Belgian beers, they returned it in droves, because they thought the beer had gone bad.

Why did Americans think that Belgian beer was bad? Because it imparted the distinctive flavor and aroma of Brett: namely horse blanket, pepper, tropical fruit, and “wet dog in a phone booth.”

But that’s not even the yucky part. 

Not only are American craft brewers making beer with horse-blanket-smelling yeast, they’re also adding bacteria into their brews.

Yup, you read that right.

Sour beer is made by deliberately infecting beer barrels with germs. 

To be fair, craft brewers didn’t come up with this strange idea themselves. They dug deep into the Vaults of History for inspiration. Back in the day, barrels weren’t cleaned between batches of beer. Dirty barrels supported the growth of bacteria such as Lactobacillus and Pediococcus, both of which are known to add a sour taste to beer. Essentially, until humans discovered germs, all beer was sour to varying degrees. American craft brewers just decided to improve upon the sour taste by making it more sour.

To increase the sourness factor in beer, craft breweries not only use strange yeast and launch germ warfare campaigns on their beers, they strengthen the effects of this harsh treatment by aging their beer longer. According to Russian River Brewing, a regular beer can be made in 35 days, but sour beer may be fermented for months, then aged for years, to give it that special tang.

What does sour beer taste like? 

What we think of as “sour” beer, actually tastes more acidic than anything else. This is because the funk-inducing manufacturing process lowers the pH of the beer.

To explain: “Most beers are in the low four pH range.” says Michael Tonsmeire, author of American Sour Beers: Innovated Techniques for Mixed Fermentations. “Sour beers are more acidic than that, mid-threes in terms of pH. It might not sound like much of a difference, but every one full point increases acidity tenfold.”

The longer the beer is aged, or the more bacteria is added to the mix, the more likely it is that the beer will make your lips pucker. I admit, I’ve only tasted sour beer once, but the one I had reminded me of a wild-berry-flavored Emergen-C, not only in terms of flavor, but also in color and fizz level.

If sour beer is so gross, why should I even bother?

Sour beer experts say that this type of beer is so good that it is known to forever ruin you on the taste of regular beer. This reason alone is enough to convince you to carry at least a few varieties if you can get your hands on them.

In addition, beer aficionados agree that the flavors and aromas differ greatly from batch to batch of sour beer, much like wine vintages. Because of this, sour beer fanatics will happily come back again and again for the same type of beer if you can keep it in stock. The difficulty, of course, is keeping it in stock, since the beer is so tricky to make.

Where can I get sour beer?

A few breweries lead the pack whenever the topic of sour beer comes up. One, Russian River Brewing, makes their barrel-aged ales from old wine barrels, then infects them with Brett yeast and bacteria. Their Consecration beer comes highly recommended.

Jolly Pumpkin is another brewery known for their farmhouse ales made with wild yeast. Their recommended brew is called Perseguidor.

Chicago’s Goose Island brewery makes a beer called Juliet, which is a Brett-yeast beer aged with blackberries; and Lost Abbey’s Duck Duck Gooze is supposed to be very good as well, though it’s also supposed to be very rare.

Have you tried sour beer? What do you think? Tweet us @UncorkdMenus.