Water, malt, hops, yeast. If you’re reading this, you probably already know that those are the four essential ingredients of beer. However, yeast was not included in that list until 1857, when Louis Pasteur discovered the secret of fermentation. Prior to that, people didn’t understand why their sugary, malty water was transforming into a heady potion that made them feel good inside, but they trusted in the mysterious powers of Mother Nature.

Fast-forward 165 years and humanity now has a vast understanding of the fermentation process. Today’s brewers have access to a wealth of scientific information and hundreds of different varieties of yeast, all of which can be used to perfectly control the brewing process and create myriad different styles of beer. With all of this innovation and development in the beer industry, and with the incredible range of products on offer to modern beer lovers, the practice of letting beers ferment ‘spontaneously’ was almost forgotten. Almost, but not quite.

A small group of breweries in Belgium maintained the tradition of brewing beers using wild yeasts and bacteria, which are found naturally in the air, on the surface of organic materials, and unique to the location of the brewery. The strain of yeast most commonly found in spontaneous fermentation beer (‘spont’, for short) is brettanomyces. Brett, along with other microorganisms such as lactobacillus and pediococcus, can be collected from the atmosphere in a variety of ways, though most commonly via a process called ‘coolshipping’. Essentially, it involves leaving wort (unfermented beer) exposed to open air for around eight to 16 hours in a large, stainless steel bath (coolship) – preferably in overnight temperatures no higher than 8°C. During that time, ambient microbes inoculate the wort and begin transforming sugars into alcohol and acids. Those reactions continue to develop for years, as the beer ages in wooden barrels.

If you’ve ever tried a spont beer, you’ll know the taste is unique. They are complex brews, renowned for being very tart, sour and dry, with all kinds of unusual, funky, floral and earthy flavours. Undoubtedly, they’re an acquired taste. But with the growth in popularity of more accessible sour beers, and with more access to exceptional imports from Belgium and Germany, they’re suddenly seeming less niche than they might have done ten or fifteen years ago.

In New Zealand, there are now a handful of breweries experimenting with spontaneous fermentation, one of the largest being Garage Project’s sister brewery, Wild Workshop, which was created especially for brewing wild beers. One of the tricky things about working with wild yeasts and bacteria is that whilst they bring amazing flavour and complexity to intentionally sour beers, they have the potential to contaminate ‘clean’ brews and destroy vast quantities of beer and equipment – meaning breweries have to be extremely careful when working with this process. Creating a completely separate brewery for wild fermentation has given Garage Project a lot of freedom to explore new techniques.

‘A fermentation playground’

“We have a lot of fun. This is the playground for fermentation here,” says Pete Gillespie, co-founder of Garage Project, who kindly gave me a tour of Wild Workshop along with head brewer Dave Bell. Gillespie and Bell’s passion for their work is palpable, and it’s clear they both have a special reverence for the wonder of wild beer. “There is something particularly magical about this,” Gillespie enthused. “If you really dig into it, people used to think that it was magic — it’s hard to not get a little caught up in that romance.”

Pete Gillespie and Dave Wood

Pete Gillespie and Dave Bell in Garage Project’s Wild Workshop

Gillespie and fellow co-founder Jos Ruffell, originally dreamed of building Wild Workshop somewhere rural. But after visiting the legendary Belgian brewery Cantillon and seeing them create their impeccable lambic beers in the middle of Brussels, they realised it was possible to cultivate urban terroir, and so settled on a site in the middle of Te Aro. “Wild Workshop is a celebration of that urban funk,” Gillespie explained. “I love embracing the inner city.” And that leads us to the topic of terroir.

Though terroir is a term most commonly used in the world of wine, it’s something that has come up repeatedly when I’ve discussed wild beers with people in the industry. The ambient yeasts and bacteria used for this type of fermentation have a major impact on the flavour of the beer, with the cocktail of microbes differing hugely from place to place; that means spont beer represents the flavour of its location in a very direct way. It is partly why these beers are so revered, and why Gillespie is so proud of the ones brewed at Wild Workshop. “The beers that we’ve made, that Dave’s produced with the coolship, they’re the pinnacle of what we do here.”

‘A slow and meticulous craft’

The topic of terroir came up again when I chatted with Brayden Rawlinson from Ninebarnyardowls in Gladstone, Wairarapa. “I’m trying to mitigate contamination from outside the area and just trying to concentrate the terroir that is Gladstone, and encapsulate it in a bottle. Which is a romantic thing.”

Rawlinson became infatuated with the coolshipping process whilst working for Birra del Borgo in the mountainous region of central Italy, close to the border of Lazio and Abruzzo. When he moved back to New Zealand in 2018, he set up a base on his parents’ property and started experimenting with a wide range of alternative fermentation methods. The Wairarapa is known more for its wine than its beer, but wild beer techniques often feel more akin to wine making than conventional brewing, and the resulting flavours often blur the lines between the two. Gueuze, a style of Belgian lambic made by blending young and old barrels of spont, is often referred to as ‘Brussels Champagne’.

Currently, Rawlinson has 32 barrels of beer ageing in his barrel room, but you can’t buy his beer anywhere – unless you’re lucky enough to catch a very limited release on tap in central Wellington. “There’s no hurry to send these beers out to the world; it’s a slow and meticulous craft,” he says. “A lot of time and effort goes into it. One of the beers that I opened the other day, I had to think about it for a bit — I just opened it like it was a beer that you’d buy off the shelf, but then I thought about it and realised that to get to this point in time, it had been five years. I had blended a four with a three with a two with a one [year-old barrel], and finished it on fruit for an additional year. That’s five years to get to that point.”

That process of blending from a range of different barrels is very common in the world of wild beer, as I saw when I visited Kieran Haslett-Moore at his brewery in Waikanae. The brewery is named North End due to the close relationship Haslet-Moore has to the north end of Kapiti Island, where he’s hosted many beer and food pairing events for visitors, and where he harvested the island’s wild microbes by inoculating small batches of wort, before transporting them back to the brewery by boat. Haslett-Moore first inoculated on the island back in 2016, and he now has a host of barrels filled with various spontaneous brews, all in different phases of the ageing process.

Kieran Haslett Moore

Kieran Haslett-Moore of North End

We tasted a one-year-old beer straight from the barrel, which was super citrusy and bright, and then tried the latest edition of Rustica, which is a blend of four, three and two-year-old barrels. Both tasted fantastic, but the blend was a little more nuanced and well-balanced, with slightly less acidity. “New-world brewers calling it ‘sour beer’ upsets the Belgians no-end.” said Haslett-Moore. “We’ve really focused on the acidity, but actually knocking back the acidity is a lot of what the process is about.”

‘It’s like old style photography’

I learnt more about the blending process when speaking with Lee-Ann Scotti, who co-owns Oamaru’s Craftwork Brewery with her partner, Michael O’Brien. Around 25 per cent of their small-batch beers are made using the coolshipping process, and they’ve attained cult status amongst beer fanatics in New Zealand. If you’re looking for authentic reinterpretations of classic Belgian ales, Craftwork is the place to be.

Scotti and O’Brien do not just blend their own barrels, they also collaborate with other wild breweries once a year as part of their Terroir Blend series. That involves other breweries – most recently Cell Division and Wilderness Brewing – sending over a barrel of (usually) one-year-old spont, which is paired with the perfect barrel from Craftwork’s own collection. All the beers are then blended and bottled, creating a complex concoction that represents multiple moments in space and time.

When I asked Scotti what appeals so much about wild fermentation, she responded: “I think it’s the mystery — you don’t know what it’s going to end up like. We make our clean beers [non-spont] and you know exactly what you’re going to get, pretty much – it’s just a production. Whereas this is a little bit more mysterious. It’s like old style photography – you take a photo with your K1000 and think ‘ooh, that’s gonna be a good one’. And then you wait, you get your packet of film, and ‘no, it wasn’t’ or ‘yes, it was’. I think we like to test ourselves. It’s like not knowing what’s in your Christmas presents.”

With all the brewers I spoke with, it’s clear wild beers hold a special place in their heart. One of the core reasons for that is the excitement of letting go of the reins, to let nature take its course. With the wealth of ingredients, equipment and knowledge available today, modern brewers can attain incredible control over the fermentation process and they’re able to create exactly the beer they want, executed to perfection. But in achieving such precision, has a little bit of magic been lost? Do we lose some of the romance when we make things so clinical? Nature is inherently unpredictable and chaotic, but in that chaos lies something perfect; something that science and technology could never truly replicate. Spontaneous beer gives us a taste of that unadulterated perfection, and when we work in harmony with nature, it reminds us that we are not separate from the environment surrounding us – we are intrinsically part of it. That reminder feels vital, and we’re lucky to receive it in such a delicious form.

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