You may not be familiar with sour beers, but, suddenly it seems that they are everywhere. Sour beers are a natural part of the evolution of craft brewing.

IPAs were the style that craft brewers first used to stake their claim against the blandness of the big brewers, but sour beers are the leading edge in craft brewing development. Although these beers have not generally been popular among either brewers or drinkers because of complex production and flavors, they are growing more popular now. That’s because brewers have mastered the challenges of brewing sours, and drinkers have come to appreciate their unusual flavors, which are definitely an acquired taste, possibly even more so than IPAs.

But people are acquiring the taste rapidly. Some retailers report that consumption of sour beers have grown 25% since 2016!

What Is a Sour Beer?

As you might guess, sour beers are partly defined by their flavor. The sourness in the beer comes from the presence of acetic acid and other acids that give them their tartness. But where does that acid come from?

Usually, sour beers gain their tartness in the fermentation process. During fermentation, microorganisms transform the sugars in beer into alcohol and other compounds. For most beers, brewers use a special monoculture of yeast that is specially bred and tightly controlled to ensure certain flavors and avoid others. But for sour beers, this isn’t always the case.

Sour beers often use wild yeast strains. In the most extreme cases, some brewers just leave their beers in an open vessel, called a coolship (originally koelschip in Dutch) and let yeast float in. Although this is risky, there are several types of wild yeast that are particularly prolific and most likely to find the beer. One of these is the genus of yeast called Brettanomyces (affectionately known as “Brett”). Other brewers will intentionally introduce this and other wild yeast strains to their beer.

Brewers also sometimes use bacteria to produce some of the acid flavors. Bacteria are normally considered a contaminant in beer, and where they’re present, they are thought to spoil the beer. And this is how sour beers taste when you first try them: like they’ve gone bad. But as you come to appreciate the flavors, you realize that this isn’t a mistake, but an intentional flavor profile.

And, it could be argued, maybe this is what beer is supposed to taste like.

History of Sour Beers

Sour beers were probably the first beers ever discovered. It’s likely that the first beers were made by letting grain ferment with wild yeasts. It was an uncontrolled process.

Later, beers were made with yeast simply taken from the previous batches, which undoubtedly included many wild contaminants. It’s only much later that some brewers worked to control the yeast and exclude bacteria from the process. However, some brewers, especially those in Belgium, stuck to the old methods of fermentation and let their beers grow wild.

In the US, tastes veered away from these complex, often off-putting flavors. In fact, it can be argued that quality control and the avoidance of these flavors is what allowed the 10 big breweries in the country to garner over 90% of the US’ beer sales during the 1970s.

But even then there were hints that Americans were interested in exploring new and different flavors in their beer. It was during the 1970s that Americans first started importing sour beers from Europe. Since this preceded the craft beer revolution, why didn’t sour beers become the flagship craft beer instead of IPAs?

Mostly, it’s because of the challenge in crafting the beers. A truly wild ferment is very difficult to control. And even if you think you’re working with a yeast like Brett, it’s not a homogenous product. There’s a lot more variation in the population and in the flavors. It might not turn out like you’d hoped. It may not even be drinkable. And when you introduce bacteria, the flavors can go even more astray. There’s a reason why many popular European sour beer styles use mixes of different batches to try to control the flavor: any given batch might not be controllable.

In contrast, IPAs are very easy beers to brew. Not only is it simple to dry hop at the end of the brewing process, the strong hop flavor can conceal many off tastes in a beer. It just makes sense that fledgling brewers would choose a style they could produce more easily and more consistently. But now that the industry has matured, it’s ready to take on the challenge of controlling the crazy and unpredictable forces of wild yeasts and bacteria. Which is why sour beers are the new hot flavor in craft beers.

Types of Sour Beers

Although beer judges may recognize as many as 10 different categories of sour beers, there are really five traditional styles of sour beers.

Berliner Weisse


This cloudy white beer style comes from Germany. It tends to be low-alcohol, and it’s made from a high wheat malt, kilned at low temperatures to avoid darkening. Because of beer purity laws, these couldn’t be brewed with fruit, but many Germans like to mix them with juices and other flavors when drinking.

Flanders Red Ale

Flanders red ales are made using a combination of yeast and bacteria that is said to be specific and controlled, but may actually vary through the aging process and exposure to wild yeast. These are aged in oak casks, with young and old beers blended to produce the desired flavor. These are often described as the most wine-like beers.


This beer originated in Germany in the 16th century. Pronounced “go-suh,” it was originally produced by putting the wort (unfermented liquid that can become beer) out in the open. Now, it is usually brewed with a combination of top-fermenting yeast and bacteria that produce lactic acid.


Lambic beers are a Belgian style that continues to be open fermented. In some types of lambic (like kriek), the yeast and bacteria can also come from fruit additions, which carry the microorganisms on their skin. These come in many variations, some of which are blended with other types of beer.

Oud Bruin

This beer gets its name from the lengthy aging process. In many ways it’s similar to Flanders Red, but it’s more often aged in stainless steel using cultured yeast and bacteria strains. They are also generally darker in color.

Is Sour Beer for You?

This is the big question everyone has about this and other styles of beers: will I like the flavor? In general, the only way to tell is to try them, but there are some people who should definitely try sour beers:

  • People who think they don’t like beer
  • Wine drinkers
  • People who like tart or sour flavors

These people are most likely to discover that sour beers are a surprisingly delicious alternative to other beer styles.

As always, we recommend the “Pick 6 Test.” Try six different kinds, reflecting different styles of sour beer. This can be a little harder for sours than for other beer styles because there are fewer sour beers available to put in a pick 6 pack. But it can also be more fun: buy some bombers and invite some friends to experiment with you (but maybe not all on the same day—that’s a lot of beer, and sours can be strong!)

If you’re looking to learn more about sour beers, we invite you to come to our store and talk to some of our knowledgeable staff. They can help you start your journey of discovery in this amazing style.