The world of craft beer is richly diverse, providing an abundance of styles that cater to a wide range of palates. Among the varied types of brews, one category has piqued interest and curiosity over the years – sour beers. But what exactly is a sour beer, and what makes it so unique? This article explores the intriguing world of sour beers, their history, brewing process, and characteristics that make them a favoured choice for many beer enthusiasts.

The Origins of Sour Beer

Sour beers are among the oldest styles of beer in the world, with origins dating back hundreds, if not thousands, of years. Before the advent of modern brewing techniques and sanitation practices, most beers had some degree of sourness due to spontaneous fermentation. This was a natural process whereby wild yeasts and bacteria present in the air would ferment the beer, creating a sour flavour.

While many beer styles have evolved to minimize this sourness, sour beers embrace it. They have a long-standing tradition in several European countries, particularly Belgium, where styles like Lambic, Gueuze, and Flanders Red Ale have been produced for centuries.

The Brewing Process of Sour Beers

The distinctive sour taste of these beers is a result of the brewing process. In addition to standard beer yeast (Saccharomyces), sour beers are fermented with wild yeast strains (such as Brettanomyces) and bacteria (like Lactobacillus and Pediococcus). These microbes produce acids that give sour beers their unique tartness.

There are several methods to introduce these souring agents into the beer:

  1. Spontaneous Fermentation: This traditional method involves leaving the unfermented beer (wort) exposed to open air, allowing wild yeast and bacteria to settle and start the fermentation process.
  2. Mixed Fermentation: Brewers add a mixture of Saccharomyces, Brettanomyces, and bacteria at the start of fermentation.
  3. Kettle Souring: The souring bacteria are added to the wort before it’s boiled. The heat from the boil eventually kills the bacteria, leaving behind their souring acids.

Characteristics of Sour Beers

Sour beers are remarkably diverse, coming in a wide range of colours, alcohol contents, and degrees of sourness. Here are a few general characteristics:

  1. Flavour: As the name suggests, sour beers have a tart, acidic flavour profile. The sourness can range from a subtle tang to a mouth-puckering tartness, often accompanied by fruity and funky notes.
  2. Appearance: Sour beers can range in colour from pale yellow to deep amber or even dark brown, depending on the specific style and any additional ingredients used.
  3. Alcohol Content: The ABV of sour beers can vary widely, from around 3% to more than 10%, depending on the style.

But importantly for us, sour beers are starting to come in low and no alcoholic versions too.

Non Alcoholic Sour Beers

With the rising popularity of non-alcoholic (NA) beers, sour beers haven’t been left behind. Many breweries are taking up the challenge of creating satisfying, complex sour beers without the alcohol content. So, what can you expect from an alcohol-free sour beer, and how does it compare to its alcoholic counterpart?

The Brewing Process

Producing alcohol-free sour beer involves similar techniques to those used for brewing traditional sour beer, with an additional step to remove or limit the alcohol content. Brewers often use methods such as arrested fermentation, vacuum distillation, or the use of specially-selected yeast strains that produce minimal alcohol. The primary goal is to preserve the characteristic sour flavour while keeping the alcohol content below 0.5% ABV.

One challenge brewers face is maintaining the complexity and depth of flavour typical of sour beers without the alcohol, which often contributes to the body and flavour of the beer. However, thanks to innovative brewing techniques, many alcohol-free sour beers manage to offer a tart, refreshing experience that can satisfy the palate of even traditional sour beer lovers.

Flavour and Characteristics

Like their alcoholic counterparts, NA sour beers offer a wide range of flavours. They can be subtly tangy or offer a robust tartness, depending on the specific brewing process and ingredients used. Fruit infusions are common in NA sour beers, adding an additional layer of complexity and enhancing the beer’s natural acidity.

While an alcohol-free sour beer may lack the full-bodied experience offered by traditional sour beers, it provides a light and refreshing alternative for those seeking to reduce their alcohol intake without sacrificing flavor.

The Market for Alcohol-Free Sour Beers

The market for NA sour beers is growing rapidly, with an increasing number of breweries releasing their own versions. Today, you can find a variety of alcohol-free sour beers, including styles like Berliner Weisse, Gose, and even Lambic-inspired brews.


So, what is a sour beer? It’s a diverse category of beer characterised by its tart, acidic profile, a product of a unique brewing process that involves wild yeasts and bacteria. From the subtly sour Berliner Weisse to the deeply complex Lambic, sour beers offer a world of flavours waiting to be explored. Whether you’re new to sour beers or a seasoned enthusiast, there’s a sour beer out there for every palate.

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