The craze for craft beer has spread across the capital in recent years, satisfying a growing thirst for high-quality beverages. But there's more to this trend than just ultra-hoppy, trendy cans of IPA. Another artisan beer movement has been gradually gaining mainstream attention.
Tank beer has hit the London bar scene. While craft beer, which has no strict definition, is often associated with strong, unique flavours and independent breweries, tank beer has little to do with the brewing process, and everything to do with how the product is transported and served directly to drinkers.
"It's bringing the brewery to the consumer," explained Pilsner Urquell's beer master and marketing boss Robert Lobovsky.
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Tank beer is pumped straight into pressurised bags that sit within tanks after it is brewed, meaning it bypasses pasteurisation and can be transported from brewery to tap within hours.
As it is transported with the same pressure from which it will later leave the tap, there is no contamination from light or added gas, leaving the exact concentration of carbon dioxide in the beer that the brewers intended.
This process maintains a fresh, straight-from-the-brewery taste that the villagers of Plzen, where Pilsner is brewed, have experienced since 1842.
Lobovsky, whose job is to oversee beer from the brewery gate until it's in the hands of the consumer, calls tank beer the "absolute pinnacle" of drinking.
The process also maintains a slight butterscotch or "diacetyl" flavour in the beer. Although the butterscotch taste can ruin beer in large quantities, for Lobovsky, it gives Pilsner's tank offerings a distinctly Bohemian trademark.
"We don't aim to have flavoured beers," Lobovsky said. "In the Czech Republic, we drink a lot of beer and we've been brewing the same beer for 174 years. So we're experimenting with different pours now, rather than flavours. The serving is as important as the brewing of the beer."
Since its introduction to the UK bar scene in 2013, almost a million pints of Pilsner Urquell have been served to beer fans. Its tanks have been introduced to bars in Cambridge, Dublin, Leeds and Manchester, as well as several in London.
However, it was only in April when Pilsner teamed up with the Chancery Lane-based Draft House that the company was able to devote itself to teaching London's beer drinkers about its three signature pours that, Lobovsky insists, create three very different versions of the same drink.
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The Draft House, which is the company's ninth tank beer partnership, contains four Pilsner Urquell tanks. Each tank contains 880 pints of fresh, unpasteurised beer.
In the "Altar of Tank", a private tank room complete with its own pouring station, drinkers can learn to pour Milk (Mliko), an almost all-foam, sweeter-flavoured brew, Crisp (Na Dvarkrat), the most common international serve that complements dinner and drinking, or Smooth (Hladinka), which Pilsner describes as a "smoother, less carbonated serve" that is perfect for "more sessionable drinking".
While UK-based breweries such as Meantime have also experimented with and moved into the tank beer scene, from the outside Pilsner Urquell seems to be pushing the trend harder than most. In May, the company launched its tenth tank beer partnership at the Draft House on Old Street.
At present, Pilsner's Czech Republic-brewed beer has roughly a 40-day turnaround. According to Lobovsky, it takes around 35 days to produce the beer. On the 36th day, the tank is shipped, arriving in the UK less than a week later.
The company declined to comment on whether the sale of the Pilsner Urquell brand from British drinks giant SABMiller would affect its logistics-heavy operations in future. The sale was announced by Anheuser-Busch InBev last month as part of a sweetener to allow the megabrew takeover to go through.