Let nature take its course

Why are so many UK breweries adopting the most primitive means of fermentation?

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So here we are: the 2020s. The millennium is not new anymore. The 21st century is not new anymore. Craft beer is not new anymore.

As the sector matures, the era of impish upstarts kicking at the shins of big beer is receding. What drinkers want now is consistency and quality, as well as flavour and independence.

This has led some of the more established craft brewers to look less like overgrown home-brewers and more like the bigger brewers they once scoffed at: quality control, standard operating procedures, all the stuff that makes beer good to drink and safe to brew. These are positive, necessary things.

But there remains a restless spirit in British brewing that pulls our most talented brewers in two different directions. One is all about growth and control; technical brewing that leads to predictable results and clean consistent beer. The other is about staying smaller, giving up control and instead embracing the unique and unpredictable results that come from mixed or spontaneous fermentation; wild brewing that leads to untamed, sour beers.

To brewers who have learned through years of training to avoid contaminating beer at all costs, taking the second path can seem like a wild gamble.

"You're breaking every rule," says James Rylance, head of Harbour's R&D project, Hinterland. "Everything that you can think of, you're trying to do the opposite and it's terrifying the first time."

James is responsible for making wild beers using Hinterland's coolship — a wide, shallow, open-topped vessel used to cool wort before fermentation. Picture a stainless steel paddling pool. These are more commonly seen in the lambic breweries of Brussels, which use very different methods to those most brewers learn here in the UK.

"You're boiling with shitloads of really stanky old hops. Then you're hot-side aerating it, which is never good. And then you're leaving it in an open tank, which is a terrible idea."


Lambic brewers don't add yeast to their beer. Instead they leave it in their coolships overnight, allowing the wild yeasts and other bacteria that are present in the environment to settle on its surface and ferment it spontaneously. This is the bit that really gives technical brewers the jitters.

"Every bone in my brewing body was like: stop it, stop it, stop doing that," says James.

Chasing dreams

Far from stopping, a growing number of British brewers are ploughing ahead. Harbour is neither the first nor the only UK brewery to invest in its own coolship. There are now 10 in all — including well-known names such as Burning Sky, Wild Beer Co and BrewDog's Overworks project — with more planned for 2020 and beyond.

"Everyone who does it tends to be pretty idiosyncratic," says James. "It attracts people who are outside of the normal beer world, or what you expect a brewer to be."

Brewing like this is definitely not a commercial decision. The beers may command a high price but require more time and effort to make and occupy a tiny niche at the top end of the market. If anything it's a vocation. But then brewers are every bit as susceptible as drinkers to getting swept up in wild beer's romance.

"There's a dream beer in my head somewhere that I've been trying to get to my whole career," says James. "It's a four-and-a-half, five percent saison. Mixed ferm. Little bit bready."

He describes a beer refreshing enough to drink by the pint and enjoy without having to think about it, but complex enough that if you wanted you could nurse it for ages. "It's super drinkable but enriching at the same time and that's an almost impossible thing to achieve."

One of James's early coolship experiments tilted at this beery windmill. He started with a spontaneous fermentation then added saison yeast to adjust the character of the beer. The result was more saison than lambic, but with a background hum of subtle complexity, like music being played far away.


Factory work

This sort of freewheeling experimentation is what makes wild beers so interesting, for drinkers and brewers alike. "I would have given up brewing ages ago if I didn't get to do this," says James. "Production's boring as shit."

By production James means technical, repetitive brewing. Churning out the likes of Gamma Ray over and over again, many times per week, with the aim of everything tasting the same.

"What's interesting is bigger breweries still hold on to the same branded narrative they originally started out with, but they're factories. They're literally just factories and it's factory work," says James.

For Burning Sky’s Mark Tranter, one of the UK's coolship pioneers, production brewing also became a frustrating experience. Although he remains proud of his previous achievements at Dark Star, in the end he felt the need to move on so he could follow his own path.

Wild brewing was an itch that grew until he could no longer avoid scratching it. “It's just being interested in something isn't it? It's like the hobbyist mentality. It’s not a route to go down if you want to make loads of money.”

Burning Sky's coolship lies just beneath the roof of a grade-two listed barn in the Sussex village of Firle. It sits amid a specially constructed oak frame from which old barrel staves hang, suspended above the beer like the mobile above a baby's crib.


You need to enjoy beers of a certain nature to enjoy these

The idea behind this odd display is that steam rising from the cooling wort will settle on these staves, which play host to a range of yeasts and bugs from the beers the barrels once held. The steam will pick up some of these microbes as it condenses back into water droplets again, then ferry them down into the coolship below. In this way, Mark hopes to encourage the growth of a house culture that gives his beers a recognisable Burning Sky flavour.

This is about as far from production brewing as you can get. “We're one of a number of people who are happy to be a bit smaller," says Mark. "We're beer first, business second. To do what we do, on paper, is completely stupid. With all the space we've got we could make a lot more beer quickly, and sell a lot more beer, and make a lot more money. But then you just become another factory.”

Sour beer's rising star

Burning Sky released its first coolship beer in 2018. The second followed in 2019, along with a set of collaboration beers, called Four Friends, that saw a base beer spend the night in Burning Sky's coolship before heading into barrels from Mills Brewing, Olivers Cider and The Kernel Brewery.

Fans have met these beers with great enthusiasm, but go beyond social media, where their appeal is amplified, and you will find plenty of drinkers who have never tried a sour beer, never heard of Burning Sky.

Mark himself is among the first to recognise these beers are not for everyone. "You need to enjoy beers of a certain nature to enjoy these," he says.

Indeed it's only in the last few years that enough drinkers have developed a taste for sour beer to support this growing end of the market.


One of the most recent breweries to install a coolship is Saint Mars of the Desert, based in Sheffield. The brewery may be new, but the brewer is not. Dann Paquette has been making beer since 1992. 

Dann recalls an occasion working for the North East Brewing Company in Boston, Massachusetts, in the 1990s. He had been brewing sour beer there and ageing it in wine barrels since late 1996. "I remember bringing a beer that we called a kriek to the Great American Beer Festival in '98 and it was the only sour beer there. It was interesting. The festival organisers had to move a trash can in front of our booth so people could dump their beer. That's what it's like to actually innovate: people spit out your beer."

Not new, not Belgian

Except it wasn't really innovation. Kriek wasn't invented in 1998. And while the current wave of coolship brewing in Britain may appear to be an exciting new departure for our brewers, coolships are not new to these lands. It may feel as though our beer culture is finally making strides into an arena long dominated by others across the water, but coolships are not an exotic Belgian import, despite what Cantillon fanboys may tell you.

Coolships have been around since medieval times. Before the invention of modern heat exchangers, breweries the world over would have routinely employed this equipment, not for souring beer but simply for cooling wort before it ferments. Coolships were no more unusual than a brewery's mash tun or its kettle.

Schematic drawings of the old Truman's Brewery on London's Brick Lane show coolships installed under the roof. These remained in use until the late 1960s at least. Elgood's brewery in Wisbech kept theirs going until 1994.

“There are probably less coolships in use right now than there ever have been,” says Dann. “In the '90s there was a brewery closing in Germany every week. Those were probably all coolship breweries.”

"If you go to Franconia, it's part of a brewhouse that would have existed probably until the 1940s or '50s," Dann explains. "It happens to have this particular other use for lambic but far and away most of the people who are using coolships today I would imagine are lager breweries in Germany.”

Indeed, coolships are of particular use to lager brewers. They allow sediment to separate out from the beer, making it clearer, and unwanted flavour compounds to evaporate away, making it taste cleaner.

Trying something different

In Sheffield, Dann is using his coolship to brew lagers, and also NEIPAs. He adds hops to the beers while they are in the coolship instead of using a hop-back because he believes it results in a cleaner beer that displays less of the sweetcorn-smelling compound, DMS, that can plague other beers.


And back in Cornwall, at Harbour, James is also experimenting: "The way I approach my coolship work isn't traditional. I use my coolship for all sorts of different stuff. It's not just a piece of equipment that must work within a lambic structure. I'm not making lambic."

What we're really seeing here are two trends that are closely related, but still not completely tied together. On the one hand, there's the coolship itself. What's interesting about this equipment is what it can allow brewers to do.

And on the other, there's the growth of experimental sour beer that sits at the high end of the market. Much of this is brewed in a coolship, certainly, but as we've seen not everything brewed in this way has to be sour. Moreover, some of the best wild beers haven't been through a coolship at all.

At Mills Brewing, brewer Jonny Mills uses an old dairy tank: "It's just a big stainless steel pot we happened to come across. For us it was more what we could get for free when we started, but it works absolutely fine: it's an open vessel that things can fall into and inoculate the wort."

Two decades after drinkers at the GABF spat out Dann's kriek, sour beers are in vogue. Bottles of Mills beer generally sell out as soon as they hit the shelves. “When we were thinking about our business plan, I hadn't foreseen the market getting to this point this quickly in the UK,” says Jonny. He had expected to rely on exports to keep the lights on, but instead found more demand here in the UK than he is able to meet.


He had expected to rely on exports to keep the lights on

Sour beer today stands as a counterpoint to the hazy hegemony that has swept through craft brewing. “Breweries in the UK market and across the world all look the same,” says James, with some feeling. “Everyone's making hazy IPAs in 440ml cans that could be from anywhere. Mixed fermentation work does give something very specific of being from a place and having an identity that can't be copied.”

James feels there is a need for idiosyncratic beers that are, in his words, a bit weird and wonky. “There's a lot to be said for cutting your own path,” he says. “I think you see that for example with Mills beers. They've caught the imagination because they're so of their place.”

Britain's wild brewers have produced some excellent beers over the last few years, some of which resemble lambic more closely than others. But the ones that seem particularly important are those that depart from Belgian influences and develop the style. For example the beer-cider hybrids that Jonny has made with Tom Oliver: Foxbic and Lambinett. And perhaps also the beers from the Four Friends collection.

It is through such beers that we might see the emergence of something new, exciting and uniquely British. “I hope that the British scene finds its own identity instead of just making versions of Belgian lambics," says James. "This is a part of the brewing culture that has always been there that was lost.”

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