To transfer wort from kettle to fermenter, Jonny Mills has to pump it out of the door of the brewhouse, through a small garden, over a fence, and into a 1000 litre tank in the back of his van. A fraction of a second later, he has to race the wort to the van to ensure the hose doesn’t slip from underneath the brick balanced carefully atop it, and douse the inside of the van in warm, sticky liquid.

“It happened once before,” he chuckles, his sheepish grin framed by his characteristic long, wavy hair. “It was a nightmare.”

This mad dash and other chaotic rigmarole typically associated with a brew day is due to Jonny and his wife and co-founder of their business Gen not owning their own brewery. Instead, the pair produce wort at Tiley’s Brewery, a tiny, cobbled-together brewery in the outbuilding to the rear of the highly regarded Salutation Inn, in the Gloucestershire village of Ham—lovingly referred to by locals as the Sally.

Once the wort is safely in the tank, the van then slowly sloshes and wobbles its way a half-mile down a bumpy country lane, to a tumbledown outbuilding in an overgrown yard in the neighbouring town of Berkeley. Here, the wort is slowly transferred to an old open-top fermenter, and if the recipe so requires, a bag of hops is weighed down with the cumbersome steel door from a tank the next room over.

“It’s a nice contrast to big shiny breweries,” Jonny says with a hint of a smile. “Making this style of beer feels right in the countryside—it wouldn’t be right making it in an industrial unit. There’s a good metaphor for Mills: if it’s not long and it’s not complicated, it’s probably not for our brewery.”

The loosely defined style of beer to which he refers is of minimal intervention. About one-third of Mills’ fermentation is fully spontaneous, and the rest is inoculated with their house culture, derived from local microbes. As varied as you can get with wild fermentation—which is to say very—Jonny and Gen’s beers are complex, rustic, and often bracing in their acidity. They can be enjoyed with either dissecting contemplation or aplomb, in the presence of both friends, or just one’s own thoughts.

Mills Brewing is, as Jonny says, very much of the countryside. The Sally is next to a farm, which has a wall of hay bales visible from the door of the brewhouse. If you’re lucky, the horse that grazes the paddock behind the pub will come and say hello. The road between the Sally and the yard crosses a brook and a small river, and on both sides, the Severn Vale stretches out beyond gently undulating fields. The Mills yard barely holds back the wilderness of the countryside trying to break in—inside the moss-covered building itself, branches crowd and huddle elderly window panes. Beneath these windows sit geriatric barrels, accompanied by all manner of re-purposed and re-homed equipment.

““If it’s not long and it’s not complicated, it’s probably not for our brewery.””

— Jonny Mills

“It is possible to make spontaneously fermented beers pretty much anywhere in the world. However, I'm sure we couldn't replicate the flavours in our beers anywhere else,” Jonny says. “There are so many minute factors which influence the fermentation: the apple trees dotting the surrounding fields will potentially house and contribute yeasts to the air; the microclimate of our location in the dip between Berkeley and Ham; our position next to the Berkeley Pill [the river that runs through the village] running along our back wall; the trees shadowing our bottle conditioning room and the thick stone walls of our corridor barrel cellar.”

“Fundamentally, it just feels right to be encouraging wild fermentation in a place where we are surrounded by nature,” Gen adds.

***

Jonny had only met Pete Tiley—the somewhat droll landlord of the Sally, and then-only brewer of Tiley’s Brewery—twice before he sent him an email inquiring about using Pete’s brewhouse in 2014. Both meetings had seen Jonny representing Bristol Beer Factory, for whom he was working as a senior technical brewer. The subject of the email in question, however, was Jonny going solo.

“[Jonny] said ‘I’m interested in setting up a wild-fermented brewery, and I’m looking for a place to do wort production. Would you be up for that?’” Pete recalls. “I said ‘yes, obviously: that sounds amazing.’ Then we drove round, looking for places; we visited farmers and land-owners that I knew, to help them find somewhere to ferment the wort.”

A serendipitous conversation between Pete and much-loved cider and perry maker Tom Oliver found Jonny and Gen their first collaboration, which just so happened to be their first brew. “On the Monday I got the email from Jonny saying he wanted to do wild-fermented beer, and on the Thursday I got the email from Tom,” Pete tells me, referring to Tom's inquiry about fermenting a lambic-style wort in his cider barrels. “I said to Tom ‘that’s way beyond my capabilities as a brewer, but it just so happens that I know a brewer who could do it.’ And that was Foxbic.”

Brewed in the autumn of 2015, Foxbic—a charming portmanteau of Foxwhelp cider apples and spontaneously fermented beer—was a significant inception for Jonny and Gen’s tiny outfit. Inspired by traditional lambic fermentation, Jonny produced a turbid mash, boiled long with aged hops, to be put into oak barrels with brightly sharp Foxwhelp juice, and Foxwhelp cider lees, and left for 18 months or so under Tom’s experienced and watchful eye.

“I was very sure that we could use some sharp cider (namely Foxwhelp—so not just any old sharp cider) to mimic the mouthfeel and drinking experience of some lambic and geuze. We were not trying to make lambic but leave the drinker with a similar experience,” Tom tells me. “After tasting it on a number of occasions we thought we were getting to a sweet point, and then decided on the final blend, put it into bottle, and gave it time for the very important conditioning.”

“Ultimately, we were amazed at how clean it was. We had thought it would be much more wild: funky, Bretty, barnyard-y. It just was not. It was a bright, vibrant, drinking explosion,” he says.

Foxbic is just that. Bright in acidity, vibrant in character, and a magical combination of two similar, yet distinct, drinks. The complete product is wonderful: sharp; complex; mellow; full of fruit sweetness and a touch of farmyard. But when you consider both constituent parts in turn, you can easily identify characteristics of each. It is a hugely accomplished blend of both beer and cider.

What came next, while Foxbic slowly matured in barrel, would become the second of two defining beers. ‘Running Beer—Still’ was Jonny and Gen’s first “official” release, their take on a draught still lambic, served on keg. A turbid mash—involving a number of temperature rests and hot water infusions, resulting in a wort containing large amounts of unconverted starch, which makes ideal food for a number of yeast and bacteria—and long boil with aged hops lent the beer characteristics familiar to lambic drinkers: it was dry and vinous, with an earthy quality, and a bold acidity.

““Fundamentally, it just feels right to be encouraging wild fermentation in a place where we are surrounded by nature.””

— Gen Mills

“It was the beer we originally set out to make when dreaming of starting the brewery. We see it as the purest expression of what we do,” Gen tells me. “When planning Mills Brewing, we were determined to make the brewery completely focused on wild fermentation, with only locally collected cultures and only barrel fermentation.”

This determination came at some cost, however. If they were to compromise on their mission for Mills, Jonny and Gen might have turned to shorter turnover, less complex, and less characterful beers to pay the bills. “We effectively chose to keep our other jobs and live in the Sally, and then in a caravan in the brewery yard, rather than make a pale ale,” Gen says with a laugh.

The caravan that sits in the yard is now used for its microwave and seating, though for 18 gruelling and, admittedly, depressing months, it was the couple’s home. Only recently did they both leave their jobs to focus on Mills full-time: Jonny hung up his boots as head brewer at Tiley’s, and Gen left her sales—and “other bits and pieces”—role at Bristol Beer Factory.

Unsurprisingly—to those who know them at least—their resolve, and passion for wild fermentation has held. Of the 30 or so beers brewed since (of which one was a second iteration of Foxbic and five have been Running Beer) not one has been a simple pale ale. Every beer is fermented with a house culture and whatever else finds its way in—from apple trees, the Berkeley Pill, or thick stone walls. And, as they go, Jonny and Gen are refining, tweaking, and learning, and either applying this to new beers or the old favourite that underpins their entire endeavour.

“We don't have any set recipes for any beers,” Jonny says. “However, I have Running Beer in mind more often than not each time we brew. Barrels become Running Beer when we come to blend. We are slowly dialling in a taste profile for what we now know to be Running Beer, but there is plenty of room for manoeuvre: we are always led by what is in the barrels, what the yeast and bacteria give us.”

Running Beer is, quite frankly, stunning. It’s perhaps the UK’s closest offering to that which it was inspired by—young Belgian lambic—whilst remaining distinct in its identity: floral and citrus notes dance amongst light fruit—white grape, apple, quince—and a slightly earthy, farmyard quality you might expect from their location. It is, though, by no means a finished product. Jonny tells me that with the third batch of Foxbic, too, they’re now close to the complexity they first hoped for.

***

That much-feted and fateful first collaboration has gone on to shape Mills Brewing in more ways than simply misty-eyed romanticism and regret from those who missed out on bottles, and a leg-up through working with a revered and much-loved cidermaker like Tom Oliver. Though initially Jonny and Gen looked toward young draft lambic, and American beers like Jolly Pumpkin’s Bam Bière and Crooked Stave’s Surette, cidermakers gradually became a primary inspiration.

“We were very much inspired by [Tom’s] approach to wild fermentation and blending,” Jonny explains, “with an emphasis on minimal intervention, letting the yeast produce an array of flavours you could never design, and then regaining some control via blending to produce the most interesting or balanced drink. This became a significant influence on how we now approach fermentation and blending. In many ways we are more closely related to cider producers than most brewers, just we use beer ingredients.”

It occurs to me that there’s wild brewing, with inoculated, bug-ridden barrel staves suspended above gleaming coolships, and mesh-lined windows to welcome in the microbe-laden breeze, and then there’s wild brewing, where the wilderness is all but held at bay. And if the countryside refuses to heed boundaries, why should Jonny and Gen?

“As with many people who enjoy wild-fermented beer, cider, or wine, what you begin to realise is it's the nature of the fermentation—rather than the substrate—that excites,” he says. “Our brewery has so much to learn from cider, wine, and any other fermented drink or food. And I don't think you can make the best beer if you only drink beer.”

This willingness to explore beyond the confines of beer is one reason why Mills Brewing “walks the walk,” in Tom’s words. “Jonny’s openness allows him to let nature do what it does best and he, like myself, acts sometimes more as a ‘matchmaker’ rather than an ‘arranged marriage,’” he says.

“The whole point is that it allows us to explore genuinely new taste and drink experiences and then we have to hope that other drinkers will allow us the freedom to follow our creative journeys.”