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A Guide to Sour Beers

Matt | 26 Jan 2018

Sourness has long been considered a fault in British beer. That’s because it’s often caused by infection. But 200 years ago nearly all beer would have had been a little bit sour due to the wild yeast strains used and bacteria-rich wooden barrels it was stored in. In fact, non-sour beer was once so rare that it was given its own name: "mild". As brewing became more professional and clinical throughout the 19th century, sourness was steadily erased.

It was a different story on the continent. Belgian and German brewers mastered sour beers, perfecting the style in now classic varieties such as Berliner Weisse, Flanders Red and, most famously, lambic beers. It is these beers that in the past decade have inspired a new generation of American craft brewers to produce "New World sours", using age-old techniques, such as spontaneous fermentation and barrel-ageing, or more controllable methods, including "sour-mashing" and "kettle souring". As British drinkers started looking for something a bit more exciting, British craft brewers, inspired by their US friends, started playing with sours.

Sour is the new buzzword of craft beer. No doubt. But its journey to get there hasn’t happened over night. The British sour movement is a mixture of time traveling, an absorption of influences from global beer cultures and a restless sense of exploration.

whos brett

Yeast and bacteria play a really important role in the creation of sour beers. Brettanomyces, often referred to as “Brett” (and you thought it was an American brewing hunk with a chiseled jaw, huge biceps and a tight polo shirt) was traditionally a wild yeast captured from the air (using kit such as a coolship) but nowadays brewers are storing it and developing it in their own labs. It works beautifully in many sour beers adding floral, earthy notes. Brett, on its own, is not enough to make a beer sour though. It will normally be used alongside two kinds of bacteria called Lactobacillus or Pediococcus, both of which create lactic acid, which imparts (you guessed it) sour flavours.


Pronounced “Berliner Vice” this is a German style that is usually very pale, cloudy and with a low ABV (often around the 3% mark). Napoleon’s marauding troops called it the “champagne of the North” for good reason.  Both yeast and lactic acid bacteria are used to ferment the beer which gives it a unique tartness. For anyone trying sour beers for the first time, this is a good place to start.


First brewed in 16th century Germany, this is a rare beer style that traditionally contains coriander and salt. It was pretty much extinct for much of the 1900s. Again it’s lactic acid bacteria pitched alongside the yeast that gives this style
it’s sourness.


The production process is similar to a Berliner Weisse except it’s aged in wooden barrels for longer and contains darker malts, giving it a reddish hue. You’ll get anything from prune juice to mulled wine spice and farmyard funk in the taste. They are probably the most intense of all the sour beer styles.


This Belgian style is the rockstar of the sour beer world. The beer writer Bill Taylor nailed it when he said “at their best, lambic beers are among the most interesting, complex drinks ever created”. Lambic beer is made using naturally occurring wild yeasts, something often referred to as “spontaneous fermentation” and then aged in wooden barrels. The term “Lambic” is protected and technically only produced in Brussels and its surrounding villages. There a lot of ‘Wild Ales’ and ‘Spontaneously Fermented’ beers inspired by Lambics made elsewhere, even if brewers can’t call them that. A blend of old and new lambics is called Gueze (pronounced “gur-zuh) and is a particular favourite of Matt’s.” 


There are now a tonne of sour beers that defy all of the traditional styles laid out in this guide. Using modern brewing methods and some crazy ass ingredients brewers are having a whole lot of fun creating beers that make you purse your lips and scream “HELL YES”. The only thing that groups them together is that they end up tasting sour.

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