Back to the Foeder

Minnesota breweries are using a historic technology to spur sour aging innovation

Mat Waddell of Wild Mind Artisan Ales // Photo by Daniel Murphy

When you settle in at the bar in Wild Mind Artisan Ales’ taproom, it’s easy to feel like you’re micrometers away from being sliced by craft beer’s cutting edge. Rows of stainless steel brewhouse equipment glint behind a glass vista to the bar’s left, and your beer will be delivered in a stemmed Teku—the latest darling in every glassware snob’s collection. 

Then, there’s the beer itself. Orange and opaque like a rich man’s Sunny Delight, Wild Mind’s Galgo finishes tart and crisp while making sure you taste every bit of its thousand-pound payload of pink guava, mango, and passion fruit. Elsewhere in the brewery, a truly avant garde wine/beer hybrid is waiting to be unleashed. 

Naturally, the key to unlocking such au courant flavors for head brewer Mat Waddell must involve some state of the art machinery, right? Well, not exactly. 

“These five are giving me my favorite sour profiles,” Waddell says lovingly as he gestures in the direction of the gargantuan oak barrels looming in Wild Mind’s cellar, “They’ve got history to them.”

These oversized relics from beer’s distant past are known as foeders (pronounced: FOO-ders) and they’re becoming a key tool for local brewers looking to probe the limits of wild cultures and wood aging. 

Size Matters

Mat Waddell filling his glass from a foeder // Photo by Daniel Murphy

Barrel-aged beer is by no means a new or edgy concept to Minnesota’s craft beer community. Indeed’s Rum King and Lift Bridge’s Barrel Aged Silhouette are big business for their respective breweries, and Town Hall features an entire week’s worth of barrel-aged beer every year. 

But despite obvious similarities, foeder-aging is a unique tradition that varies from these boozy barrel-aged beers we’re familiar with in a few key ways. The most obvious is their size.    

“The smaller the barrel, the more surface area you have, and the more oxygen can permeate into that beer,” Waddell says. “The bigger the barrel, the less oxygen, the slower the aging, the more consistent of a product you have.“

In a standard 60-gallon barrel, aging tends to be a rapid process that can lead to harsh flavors similar to those we normally associate with a young whiskey, albeit in a spirit-neutral vessel. Foeders give brewers a handbrake for the aging process, as well as the ability to amplify their capacity, once they’ve dialed in a recipe. 

There’s no official designation for the size at which a large barrel becomes a foeder, but former New Belgium head brewer Peter Bouckaert—who brought his love of sour beer and, somehow, several massive foeders to Colorado after working as a brewer at Rodenbach in Belgium—pegs it at around 159 gallons in his paean to cooperage “Wood & Beer: A Brewer’s Guide.” The largest foeder ever constructed was a warehouse-sized monstrosity used by an aperitif maker in France, and it reportedly held a capacity of up to 1 million liters.

Waddell’s five favorite foeders began their lives just outside of Venice, Italy. They had fruitful, 30-year careers aging wine in the Tuscany region, and then landed in Minnesota in 2016, just in time for Waddell’s oak cellar to be built around them. It’s a good thing these old-timers were early to the party, because they’re way too big to have fit into the door. 

“These were cheap as chips—they were probably the cheapest piece of equipment in this entire brewhouse,” Wild Mind’s brewer says with a hint of pride. “When these foeders arrived, they were dry as all hell. I could see daylight through the cracks in the stock.”

Nursing the old barrels back to health was catnip for Waddell’s high-revving engineer’s brain. He scoured the internet, translated a care guide from the original Italian, and placed a few calls to Schells’ assistant brewmaster and Noble Star sour guru Jace Marti.

Cypress foeders at Schell's Starkeller brewery // Photo by Kevin Kramer

Cypress foeders at Schell’s Starkeller brewery // Photo by Kevin Kramer

Marti proved to be a crucial resource, having started resuscitating his brewery’s venerable Starkeller cypress foeders in 2008 after exhuming them from the historic brewery’s basement and a dirt-floor shed. 

Purchased by the Schell family in 1936, these 10 foeders were originally used as budget-friendly alternatives to steel tanks for lager fermentation. The massive 12-foot-tall, 10-foot-wide, 4,350-gallon vessels were used continuously for that purpose until 1991, when cleaning standards and old age finally caught up to them. 

Marti was inspired to repurpose the cypress tanks as foeders by his studies in Germany and Belgium. Rodenbach brewery’s centuries-long use of foeders for their Flemish red ales—mixing old and young fermentations to create funky yet drinkable beers like their famous Grand Cru—left a particular imprint. 

Waddell’s foeders have a range of capacities, with an average of around 900 gallons, as do the ones recently installed in Modist Brewing’s state-of-the-art brewhouse in Minneapolis’ North Loop neighborhood. Surrounded by high-tech equipment like a ROLEC dry-hopping system and a brand new centrifuge, Modist’s head brewer Keigan Knee might be most excited about his freshly constructed oaken vessels from St. Louis’ Foeder Crafters of America. 

Keigan Knee stands next to the foeders at Modist Brewing Company // Photo by Daniel Murphy

“I was captivated by the beauty of them, to be honest,” Knee says of his new toys. “We wanted to play around with clean and sour beer in more of our regular production, to see what we could coax out of that wood.”

But while foeders impart wood flavors and characteristics at a slower rate than smaller oak barrels, Knee cautions that the brewer still needs to have a watchful eye so the barrel doesn’t overwhelm the beer. “Wood will actually bitter your beer, so if you put too much hops in it, now your beer is going to be perceived as over-bitter.

“We have a beer that’s in [our foeder] right now, we didn’t put any hops in there at all until dry-hopping,” Knee continues. “We’re gonna rely on that balance of the tannins in the wood, like you would a wine, to help balance it out.” 

To Clean or Not To Clean?

At Wild Mind, Waddell’s nine total foeders are all inoculated with a veritable zoo of funk-inducing microbes, and each has its own distinct flavor that he can blend to balance acidity and sweetness. Like a chef jealously guarding his or her perfectly seasoned cast-iron pan, Waddell’s approach strikes a delicate balance of allegiances between his bugs and the cleaning standards of a professional brewery. 

“I consider myself to be a farmhouse brewer,” he chuckles. “I don’t clean my tanks like other brewers. I’m sure it irritates the shit out of my staff that work on the stainless steel side.” 

Over in the North Loop, Keigan Knee is taking a contrasting approach and running his foeders bug-free, utilizing a few technological updates to traditional foeder construction, like cooling plates and internal cleaning systems. “I’m a big car and motorcycle guy. It’s fun to take new age motorcycle parts or techniques and put them into a vintage bike,” Knee says. “You wanna pay respects to the old school, where everything came from, but make it your own.”  

Staying clean and cold allows Modist to produce their unique oak-fermented Pilsner foeder beer, Just You Wait. 

“That sat on wood—fermenting, conditioning, and lagering—for almost two months,” Knee says of the Pils. “The flavor that you get is this smooth, slightly woody, dry crisp finish on the end. That’s the wood.”

Knee inspects a freshly drawn glass of beer from the foeder // Photo by Daniel Murpy

Foeder Crafters of America owner Matt Walters says these kinds of tech-forward features are quickly becoming standard upgrades for his customers as business doubles every year. Walters jokes that he’s happy to have a monopoly for the moment but that he works hard to keep his products below the price point of an equivalently sized stainless steel tank to help entice brewers off the fence. 

Still, it’s far from a no-brainer for local breweries to invest in one of Walters’ creations or try their luck finding a used foeder. For one, there’s the simple factor of space constraints, and the increased difficulty of continuous cleaning of such large vessels. It doesn’t help that sour beers are still a controversial choice for some Minnesotan palates, or that Walters’ most popular 30-barrel model starts at just over $10,000. 

But who said brewing had to make perfect economic sense? Whether they’re drawn in by a sense of history or the spirit of innovation, some of Minnesota’s brewing community find themselves falling for foeders. 

“You just cannot get the same flavors and profiles from doing it in a stainless steel tank,” Waddell says. “It’s exciting, it’s beautiful, it’s ornate, it’s difficult: it’s all of these fun things.”