How are sour beers made?

The Art of Tart: Discover How Sour Beers are Made

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In the vibrant world of craft beers, sour beers have captivated the palates of beer enthusiasts. They offer a tangy twist to the traditional brew, creating a fascinating balance between sour and sweet, which leaves one wondering – how are sour beers made? In essence, sour beers are crafted by deliberately introducing wild yeast strains and bacteria during fermentation, giving them their unique acidic, tart character.

Delving into the Sour Realm: The Intricacies of Brewing Sour Beers

Sour beers are like the wild child of the beer family – they can’t help but stand out from the crowd. And that’s all down to the crazy chemistry happening behind the scenes.

Originating in Belgium, the art of brewing sour beers has a rich history. While modern brewers have adopted the technique worldwide, they still use age-old methods for brewing these tart beverages. Like most beers, the process begins with malted grains, water, and hops. However, the real difference lies in the fermentation stage.

In the fermentation process, brewers typically introduce brewer’s yeast, known as Saccharomyces. Yet, crafting sour beers invites a wildly different set of characters to the party. The show’s real stars in sour brewing are wild yeasts like Brettanomyces and bacteria such as Lactobacillus and Pediococcus.

Brettanomyces contributes earthy and funky flavours to the mix, while Lactobacillus and Pediococcus produce lactic acid during fermentation. This acid imparts the tartness that distinguishes sour beers from their sweeter counterparts. Ok, don’t worry – I will relax with the Latin words.

In traditional brewing, these wild yeasts and bacteria are considered contaminants, spoiling the beer. However, in the realm of sour beers, they’re crucial contributors to the brew’s unique character.

Brewers further enhance the sour beer’s complexity by ageing it in oak barrels. They often use barrels previously used for wine or spirits, which impart additional flavour profiles into the beer. This process can take anywhere from a few months to several years. The ageing period allows the wild yeast and bacteria ample time to metabolise the sugars, adding depth and sourness to the beer.

So, the next time you savour a pint of sour beer, you’ll know the intricate dance of wild yeast and bacteria that happens behind the scenes. The art of brewing sour beers is not just about combining ingredients. It’s a testament to the creativity and patience of the brewer, balancing a delicate ecosystem to achieve the perfect tartness. After all, the best things in life are worth waiting for, aren’t they?

Defining True Sour Beer: Beyond the Taste

Do sour beers have a lot of sugar?
What is a true sour beer?

Now that we’ve got the brewing basics down, let’s explore what sets a genuine sour beer apart. It’s not just about that tangy taste – there’s so much more to the story.

While the characteristic tartness undeniably defines sour beers, a true sour beer’s identity isn’t simply about its sharp, zesty kick. Instead, it lies within time, microbial influence, and the brewer’s craft.

Remember the wild yeast and bacteria we discussed? Their significance extends beyond mere fermentation. They’re the foundation of a true sour beer. While some contemporary brewing practices may use flavour additives or artificial souring techniques, a traditional sour beer relies solely on these microbes for its unique flavour.

The balance of these microorganisms is key. Too little, and the beer lacks its signature tartness. Too much, and the beer becomes overly sour, masking the underlying malt and hop flavours. The skill in brewing an authentic sour beer is carefully guiding this microbiotic dance, orchestrating their population to create a melody of complex flavours.

Also, as we mentioned before, a genuine sour beer requires patience. Instant gratification is not in the vocabulary of a true sour beer brewer. The extended fermentation and barrel ageing process, which can last from several months to years, is an essential aspect of its identity. This duration allows the wild yeast and bacteria to fully work their magic, infusing the beer with layers of complexity and depth.

As you sip a sour beer, consider the intricate interplay of flavours, from the tangy kick of lactic acid to the subtle hints of oak from the barrel. Recognising these elements helps you appreciate each drop’s journey from the barrel to your glass. Indeed, understanding the true nature of sour beer extends far beyond its tangy taste—it’s an appreciation of a centuries-old tradition and the craft of skilled brewers.

Sugar and Sour Beers: Debunking Myths

Having explored the essence of true sour beers, let’s now debunk a common myth: are sour beers high in sugar?

It’s easy to see why many might believe so. Sour beers often exhibit a tangy-sweet balance, a fruity complexity that can lead some to equate them with high sugar content. However, this is a common misconception.

In reality, the fermentation process used in brewing sour beers generally reduces sugar content. Here’s how: The wild yeast strains and bacteria we’ve discussed contribute to the beer’s characteristic tartness and are also remarkably efficient at metabolising sugars in the wort. These microorganisms can consume complex sugars that regular beer yeast can’t process, making sour beers typically drier and lower in residual sugar.

The perceived sweetness in some sour beers often comes from the beer’s flavour profile itself. Fruit additions, like cherries in a Kriek or raspberries in a Framboise, can give the impression of sweetness without significantly increasing the beer’s sugar content. It’s also worth noting that many sour beers utilise a process called “kettle souring,” where the beer is soured in a sterile environment before being boiled, effectively stopping the souring process and allowing for greater control over the beer’s final sweetness.

So, while sour beers can exhibit a sweet-tangy equilibrium, they typically aren’t high-sugar beverages. The brewer’s skill lies in their ability to create this balance and complexity, playing with perceptions of sweetness and sourness while offering a low-sugar beer.

Understanding this intricacy allows for an even greater appreciation of sour beers. It’s a testament to the brewer’s craft—managing the dance of flavours to create a beverage that challenges, surprises, and delights the palate.


Sour beers offer an exciting divergence from the traditional beer flavours, thanks to the innovative brewing techniques that accentuate their tart, acidic profiles. In essence, true sour beers are a result of the careful orchestration of wild yeasts and bacteria during fermentation. At the same time, their sugar content is primarily determined by the balance struck during the brewing process. Indeed, the art of making sour beers is a testament to the versatility and creativity in the world of craft brewing.

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