Meet the Colorado brewer who turned America sour
In 1996, a Belgian brewmaster arrived in Fort Collins, Colorado with a master’s degree in fermentation science, a decade of experience at one of Flanders’ most revered sour breweries, and an idea that struck most American craft brewers as borderline insane: deliberately souring beer. Three decades later, sour beer is a fixture of the American craft beer landscape, and Peter Bouckaert is the reason why. This is the story of how one brewer’s stubborn devotion to wood, wild yeast, and patience changed what American beer could taste like — and where he’s making beer today.
In This Article
Who Is Peter Bouckaert?
Peter Bouckaert grew up in Belgium drinking low-alcohol table beer at school lunches — a completely normal part of Belgian life that gave him an early, casual familiarity with beer most American brewers of his generation never had. He set out to study bioscience in college, then changed course after walking past his university’s brewing department, eventually earning the equivalent of a master’s degree in brewing and fermentation technology from the University of Ghent, plus a Quality Engineer degree from CKZ Kortrijk.
His professional education continued at Rodenbach, the roughly 200-year-old Flemish brewery renowned worldwide for its sour Flanders red ales — beers aged for years in massive oak foeders, blended young and old to achieve their signature tart, complex character. Bouckaert spent close to a decade there, eventually becoming brewmaster, absorbing a discipline of patience and wood-aging that essentially no American brewery practiced at the time.
Definition
Flanders Red / Flanders Brown Sour Ale
A traditional Belgian beer style, originating in West Flanders, characterized by long aging in large wooden barrels or vats (foeders) where the beer is colonized by wild yeast and bacteria — primarily Lactobacillus and sometimes Brettanomyces — that produce a distinctive sour, vinous, almost wine-like character with notes of dark fruit, balsamic vinegar, and oak. Flanders red ales (like Rodenbach) tend to be lighter and more acetic; Flanders brown ales (sometimes called oud bruin) tend to be maltier and rounder. Both styles are frequently blended — young, fresh beer mixed with older, more sour beer — to achieve balance, a technique directly analogous to the solera system used in sherry production. The style is one of the most direct points of overlap between beer and wine in terms of production philosophy, aging requirements, and flavor profile.
Bouckaert first crossed paths with New Belgium’s co-founders when Jeff Lebesch, on a trip retracing the Belgian cycling tour that had originally inspired New Belgium’s founding, visited Rodenbach and toured the brewery. In 1996, New Belgium sponsored Bouckaert and his wife Frezi to fly to a Craft Brewers Conference in Boston to share a Belgian brewing perspective with an American industry then almost exclusively shaped by German and English traditions. New Belgium was also quietly looking for a new head brewer. After the conference, Peter and Frezi rented a van and drove cross-country to Fort Collins — stopping at Niagara Falls and Chicago along the way — to see the brewery and decide whether the opportunity was real. Bouckaert arrived for his interview, by his own account, in ripped jean shorts, and was offered the brewmaster job before he flew home.
How Did La Folie Change American Beer?
When Bouckaert joined in 1996, New Belgium’s entire portfolio consisted of five Belgian-inspired beers: Fat Tire, Old Cherry, Abbey Dubbel, Tripel, and Sunshine Wheat. He immediately began expanding the lineup and, in 1997, made a decision that struck most of the American craft beer industry as commercially reckless: he started brewing a sour.
There was essentially no market for sour beer in the United States at the time. New Belgium began collecting wooden foeders for aging and cultivating its own strains of souring bacteria — Lactobacillus and Pediococcus — alongside a “zoo” of Belgian sour yeast strains Bouckaert had been quietly saving. His first attempt at a kettle sour failed outright. The beer that eventually succeeded, a Flanders-style sour brown aged in oak for one to three years, took its name — La Folie, French for “the folly” — from a one-off collaboration beer New Belgium had previously made with the now-defunct Redfish Brewhouse of Boulder.
La Folie debuted at the 2000 Great American Beer Festival and won a bronze medal in the Belgian and French-Style Ales category — there was no dedicated sour category yet, because there weren’t enough American sour beers to justify one. It went on to win gold at GABF in 2001 and 2002, and became one of the most recognized and highly rated American sour beers of its era. New Belgium co-founder Kim Jordan later recalled tasting it for the first time and not knowing what people would make of it. They were challenged, at first. Then they weren’t.
By the Numbers
The Growth of American Sour Beer
When La Folie first won its GABF medal in 2000, there was no American-style sour category at the competition at all. By 2016, the American-Style Sour Ale category at GABF drew 142 entries — and Nielsen reported that sales of sour and American wild ale-style beer grew 73% in a single year (2015). The category has continued to mature since, with multiple breweries across the country now operating as dedicated sour-only producers, and barrel-aged and wild-fermented beer programs becoming standard offerings at breweries that would never have attempted them a generation earlier. Few individual brewers can claim as direct a hand in launching an entire American beer category as Bouckaert can with sour ale.
What Did Bouckaert Build at New Belgium?
Sour beer was only one piece of Bouckaert’s 21-year tenure. He brought consistency discipline to a brewery that, before his arrival, was still finding its footing as a production operation — New Belgium co-founder Kim Jordan has credited him directly with teaching the company how to brew beer that was reliably consistent from batch to batch, a foundational skill for any brewery aiming to scale.
He also reached back into European brewing history for inspiration. When a 16th-century Belgian black lager recipe surfaced in a centuries-old brewing manuscript, Bouckaert helped recreate it as 1554 Black Lager in 1997 — a beer that required him to adapt New Belgium’s then ale-only equipment to lager fermentation for the first time. He was, by his own account and others’, an early advocate for brewing hoppier beers outside the Belgian tradition as well, pushing New Belgium into IPAs, Czech-style lagers, and fruit and spice beers well beyond his Flemish training.
Under his direction, New Belgium’s sour and wood-aging program became, by wide industry consensus, the most ambitious in American craft beer. The Brewers Association recognized his contribution to the field directly, awarding him the 2013 Russell Schehrer Award for Innovation in Brewing — one of the industry’s most significant individual honors. He also co-authored Wood & Beer (Brewers Publications, 2016) with Dick Cantwell, co-founder of Seattle’s Elysian Brewing, drawing on roughly two years the two spent traveling the world researching barrel-aged and wood-fermented beer traditions.
Over Bouckaert’s tenure, New Belgium grew from a regional Colorado and Wyoming operation producing roughly 31,770 barrels annually into the fourth-largest craft brewery in the United States, brewing more than 900,000 barrels a year and reaching distribution in nearly all 50 states.
Where Is Peter Bouckaert Now?
After 21 years as New Belgium’s brewmaster, Bouckaert left in 2017 — not for a competing major brewery, but for something dramatically smaller. Alongside Zach Wilson and Laura Sickles, who had previously run a short-lived Fort Collins operation called 1933 Brewing, Bouckaert co-founded Purpose Brewing & Cellars, a small farm-style brewery built specifically around sour, barrel-aged, and small-batch beer — the parts of brewing he found most personally compelling, freed from the scale demands of running a 900,000-barrel operation.
“I said from the get go that I wanted to stay as long as I can learn,” Bouckaert said at the time of his departure. “Now I want to learn new things.” Kim Jordan, for her part, wished him well publicly, noting the genuine creative partnership the two had built over two decades.
Visit Today
Purpose Brewing & Cellars
Located at 4025 S. Mason St., Fort Collins, Colorado, Purpose Brewing & Cellars remains active and operating as of 2026, nearly a decade after its founding. The taproom rotates four to five unique beers weekly, with a barrel-aged beer and, most weeks, a sour beer consistently on tap — a direct continuation of the wood and sour focus Bouckaert spent two decades building at New Belgium, now at a scale where he can personally oversee every batch. Visitors have reported being served personally by Bouckaert himself behind the bar — a level of direct access to one of American craft beer’s most significant brewers that simply wasn’t possible during his New Belgium years.
What’s Happened to New Belgium Since?
New Belgium’s story has continued to evolve significantly since Bouckaert’s departure. In 2019, after operating as a 100% employee-owned company since 2012, New Belgium’s employee owners voted to sell the brewery to Lion Little World Beverages, the Australasian craft beer arm of Japanese beverage giant Kirin, in an all-cash deal reportedly valued between $350 million and $400 million. Kim Jordan cited the financial pressures of sustaining an employee stock ownership plan amid intensifying competition — by then more than 7,500 craft breweries nationwide — as central to the decision.
Since the Lion acquisition, New Belgium has continued to grow, with Lion later adding Bell’s Brewery to the same portfolio, positioning the combined company among the largest craft beer groups in the country by sales volume. New Belgium has weathered real operational challenges as well — its Asheville, North Carolina brewery was flooded for five months following Hurricane Helene in September 2024, with the company crediting a rapid coworker-led recovery effort for getting the facility back online. Under current CEO Shaun Belongie, New Belgium entered 2026 with a five-year strategic plan focused on its core Voodoo Ranger lineup and 2030 sustainability targets — a different company, by ownership and scale, than the one Bouckaert helped build, but one that still credits his sour and wood-aging program as foundational to its identity.
Frequently Asked Questions About Peter Bouckaert and American Sour Beer
🍺 Sour Beer Terms — Quick Reference
Key vocabulary for understanding sour and wood-aged beer
| Term | Meaning |
|---|---|
| Foeder | A large wooden vat, often holding thousands of gallons, used for long-term aging and wild fermentation of sour beer |
| Lactobacillus | A bacteria that produces lactic acid during fermentation, the primary source of tartness in most sour beer styles |
| Brettanomyces (“Brett”) | A wild yeast strain that produces funky, barnyard, and fruity character; common in Belgian and American wild ales |
| Flanders Red/Brown Ale | Traditional Belgian sour ale styles aged in wood, characterized by tart, vinous, dark fruit character |
| Solera-style blending | Mixing young and old beer (or wine/sherry) to balance intensity and maintain consistency across batches |
| American Wild Ale | A broad US-recognized category for beers using wild yeast and/or bacteria fermentation, often barrel-aged |
