Taking the bitter with the sour

The beer world is in thrall to two tastes, bitterness and sourness. Bitterness provided by modern hop strains is the flashy avant-garde of the beer revival. The mysticism and complexity of the hop and its resinous acids is what makes beer bitter and provides the delicious citric, piney or floral notes that have driven a new wave of pale ales in the US and subsequently in the UK.

Sourness lurked in the higher echelons of connoisseurship, treasured by aficionados but challenging to newcomers. Found mostly in complex, bracingly sour Lambic beers from Belgium, sourness is created by the introduction of wild yeast to ferment beer, just like it is with sourdough bread.

The voracious nature and unpredictability of wild yeast is something that the modern brewing process works very hard to eliminate, to the extent that sourness is associated with spoiled beer. This is correct in many cases, but at one time all beer utilised wild yeast. The very discovery of fermentation was the realisation that something magical in the air was able to change sugar into intoxicating alcohol. The by-products of this process give us a good part of the complex flavours in beer. Over time, the myriad strains of wild yeast were able to be separated and corralled into useful areas which could be controlled by brewers and applied to different styles of beer. This gave rise to our modern ale tradition.

Only in a few areas of Europe has an appreciation of brewing sour beer persisted. The Senne valley outside Brussels in Belgium, where the great and complex Lambic (wild yeast) beer brewers and blenders have remained almost unchanged since the 1500s. Here brewers utilise wild yeast – abundant in the air and lightly covering cobwebs and even tools – in the brewery to spontaneously ferment the beer. The fermented beer is then served straight or barrel aged. No small amount of skill is expended in the blending of young and old Lambic beers to create majestic and mouth puckeringly sour Gueuze beers – the grand cru champagnes of the beer world.

In the UK, the country that gave one of the most important wild yeast strains, Brettanomyces, its name, elements of sourness persisted in rare Old Ales and Stock ales. Wild yeast was introduced by ageing strong beers in wooden casks, porous to the Brettanomyces and the bacteria Lactobacillus whose actions create the sour, ‘farmyard’ and ‘horse blanket’ flavours unattainable with regular yeast strains.

These beers, brewed as they have been for years and years are still somewhat niche styles. What has taken off recently and surprisingly are the German style sour wheat beers such as tangy Berliner Weisse and the lesser-known salty & sour Goze beer. Different techniques are being developed for souring beers that allow brewers to experiment with sourness in a more controlled environment.

In the UK today sour beer is making somewhat of a comeback. The natural curiosity of brewers and the rise and rise of beer as a gastronomic entity has taken some forward thinking breweries down a path that is celebrating and breathing new life in to sour beers. The naturally refreshing nature of sourness is made even more accessible, often by the addition of fruit; something pioneered notably by Brodies breweries’ ‘London Sours’. In addition to this, many of the brewers embarking on the quest to revive these delicious styles of beer are brewing at very low ABVs. This casts a wider net in terms of drinkers and allows the beer to slip into a lower tax category, thus making the beers much cheaper than the champagne-like prices of Belgian Lambics and, in particular, Gueuze.

Grand wizard of the London beer scene, Evin O’Riordain at the Kernel brewery, puts the revival down, in the main, to curiosity and the simple fact that he brews beer he likes to drink. ‘Anybody with any sense loves sour beer,’ and it’s this appreciation and a slight sense of obligation that drives him to push the envelope and move down paths rarely trodden by the vast majority of British brewers. The Kernels London Sour is the first step in a process that will lead Evin towards blending aged sour beers and emulating the brilliance and complexity of the Belgian tradition, with a modern twist.

Up north, two breweries in particular are experimenting with sour beer. Buxton, with their lactobacillus inoculated Berliner Weisse – Der Nord Sekt. It’s a delightfully snappy, light beer with interesting elements of sourdough, earthy notes and lemony funk.

Over in Yorkshire one of the most distinctive and forward thinking new breweries, Magic Rock, are perfecting Goze beer. The style originates in Leipzig and was somewhat mysterious, it took an Italian brewer, Giada Maria Simone, to come to Huddersfield to revive it. Goze is a spontaneously fermented wheat beer that has a salty tang alongside the sourness – originally a result of spontaneous fermentation alongside local water with a very high mineral content. This extra aspect makes an intriguing brew, where sour funky flavours interplay with added fruit in the form of gooseberry, grapefruit or lime, and a salty smack around the lips on the finish. The beer is called Salty Kiss.

All this is exciting and not many beer scene-sters would have ever thought that sour beer would take hold as much as it is doing. The London sour scene is limited somewhat to rather low ABV beers. Whilst refreshing, they eschew the fact that most drinkers perhaps prefer a little more alcohol in their drinks; a feel as much as a flavour. But it seems plans are already in place to move this on. The ability to provide a sour fruit beer around 5% will furnish some brewers with a massive opportunity to get the beers to a much wider audience.

Wherever we end up, sourness is here to stay and is more accessible than ever. It makes sense really that, in an industry dominated by wine and fruity drinks, beer would rediscover its tangy earthy roots and yet widen its appeal to a new and excitable generation of drinkers.