Goose Island Brewing Co.

It doesn’t take a wizened beer nerd to know that sour beers -- those tart little wonders brewed with bacteria cultures or wild microorganisms instead of run-of-the-mill yeast -- are on the up and up. Whether in the form of fruity Belgian lambics, salty German goses, or American wild ales aged in tequila barrels, these loveable palate-punchers are appealing to more of today's imbibers than ever before. And as more breweries throw their hats into the tangy ring, many are expanding their fleets to meet this growing demand.

But breweries aren't simply buying up more spent wine casks or doubling down on bottle releases -- they’re also stocking up on dozens of massive wooden tanks that, at first glance, look more like Frodo-approved real estate than any piece of brewing equipment most modern drinkers have ever seen.

As it turns out, these Hobbit hole stand-ins are called foudres (or foeders -- pronounced FOOD-ers). The hulking, medieval-looking wooden vats were originally used for fermenting and storing wine, but can similarly be used for fermenting beer. It’s a method that Belgian brewers have been employing for ages -- most notably the folks at the Flander’s red-centric Rodenbach. And in recent years, foudres have become increasingly popular toys for breweries producing barrel-aged sour beers.

How breweries use foudres

Here’s the gist: A great number of sours spend the first year or two of their lives bubbling away in standard-sized oak barrels, a process that allows pitched bacteria to take its time chewing through all that sugary malt base until the stuff inside is transformed into a beautifully acidic boozy brew. In its most basic sense, a foudre is an oak barrel on steroids, turned upright and fitted with a spout and a lid for easier access. Bacteria-infected baby beer goes into the foudre, sits around, and eventually ferments into grown-up beer. Then it’s piped out and either bottled up or blended with other like-minded liquids to make a finished product.

But if foudres are essentially just large barrels, why are so many American breweries (many of whom already boast substantial barrel programs) interested in adding these big boys to their collections?
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Bigger is (sometimes) better

One of the factors driving the foudre craze is the idea that you can brew bigger batches of barrel-aged beer without taking up a ton of floor space. While the average wine barrel might max out around 225 liters a pop, a single foudre can hold as much as 220 hectoliters (1 hectoliter = 100 liters) of sweet, sweet suds at any given time. This allows brewers to test out new recipes without sacrificing an entire rack’s worth of smaller vessels.

“We knew New Belgium had been doing it for years, so part of it was just experimentation. And something exciting for us to play with,” explains Bill Savage, the lead brewer for Goose Island Beer Co’s barrel division. Savage oversees nine foudres ranging in capacity between 50 and 80 hectoliters. “From our standpoint, it's a nicer volume for trial beers. We don't have to take up hundreds of wine casks, all of which we’re already using. You can do a lot with casks, but you have to forklift or lug them around. These are stationary. You can use pumps [to get the beer out] -- it's just easier.”

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Size might be a major plus for brewers tasked with satisfying today’s sour-thirsty crowds, but that wasn’t always the case. When New Belgium Brewing Co. Wood Cellar Director and Blender Lauren Woods Salazar first began her pioneering foudre adventure back in 2000, she wasn’t exactly convinced that bigger was, in fact, better.

“When we started getting foudres, I still had no idea what was happening. I was like, 'Why do we need these? More sour beer? Nobody likes this,’” she remembers. “But the great thing was that as we collected them, people actually started liking sour beers. So by the time we got to 65, people actually wanted to talk about, write about, and drink sour beer. Before that, it was just very niche beer drinkers. That's not the case anymore.”

Woods Salazar soon grew to love her behemoth darlings, figuring out how to get the most out of their strange vertical construction and depth.

“The beer in the foudre becomes kind of like a mother, like your wood-aged sour core,” she says. “You can continuously add one or two inches of beer to the top, so you always have this very sour base you can then blend with fruit beers, or beer that’s been fermented in whiskey barrels, cognac barrels, tequila barrels -- anything that will give you more complex, layered notes. It's a real workhorse, especially if you have a 25 hectoliter foudre and you're blending it into just five hectoliters of richly flavored beer.”

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It’s an “oxygen-free zoo” for the good bugs

Height isn’t a foudre's only advantage. According to Matt Walters -- co-founder of Foeder Crafters, the Missouri-based company that specializes in constructing handcrafted American Oak foudres -- the vessel’s thick walls and unique, tank-like features help eliminate excess oxygen, giving it an edge over comparatively vulnerable barrels.

“A foeder is twice as thick as a wine cask and has a much lower surface area ratio of wood to beer. It also has fittings and valves so it can be purged with CO2 and filled like a regular tank instead of bung holes, which can leak air,” explains Walters. “Exposure to oxygen spoils the beer because it causes the bacteria make acetic acid (i.e. vinegar). Unlike foudre-fermented beer, when you blend wine casks together, there is almost always one bad one in the batch that got too much oxygen.”

For Savage at Goose Island, this stark difference took some getting used to. He eventually found that if fermented correctly, a foudre-fermented beer’s lack of oxygen can result in more subtle flavors developed over a longer period of time.

“With a foudre, you're going to pull softer characteristics, and it’ll take a little bit longer to get those,” he notes. “Something really rich or heavy with a lot of qualities that lend themselves to oxidation are probably better left for cask aging.”

Maintaining the perfect conditions for your bacteria to do its thing is crucial for perfecting the art of sour beer, and foudres, it seems, know exactly what they’re doing. “A foudre is basically an oxygen-free zoo for your favorite wild yeast and bacteria,” Walters adds. “And the brewers are the friendly, bearded zookeepers.”

It's a literal work of art

Walking into Goose Island’s football field-sized barrel house is breathtaking to say the least -- there are rows of bourbon barrels housing delicious stouts as far as the eye can see, buffered by stacks of wine casks stuffed with pounds of fresh, aromatic fruit. And stashed away in a far corner are nine modest foudres, standing tall and elegant above the round, waist-high masses.

“People talk about how beautiful they are all the time,” says Savage. For Goose Island, the aesthetic angle is no small thing. They’re in the midst of finishing up a lavish event space inside the barrel house, and showcasing their prized foudres is an obvious priority. “It's cool to be able to have a functioning piece of art in your brewery.”

If you think a cluster of nine foudres are impressive, try taking in New Belgium’s robust double-digit lot. Even though she’s been working with the towering vessels for well over a decade, Woods Salazar still can't get enough of her enchanting beasts.

“When you’re encapsulated within the foudres, looking around, it's the same feeling as being in the middle of a forest and not seeing the road -- it's a such special experience,” she marvels. “I love it so much that I literally moved my entire office in there. I had an office with a door that overlooked the brew house. But one day, I just thought, ‘I need to be among the foudres.’ So I moved my desk, put some shelves against the concrete walls, and now I live in the foudres. They're completely surrounding me.”

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It's a true labor of love

As Savage says, foudre-fermented beers do take a a bit longer to mature, but the payoff is well worth the wait time. And in the meantime, the amount of control a foudre allows -- they’re much easier to taste, monitor, and top off than regular barrels -- gives brewers the chance to really get to know their new additions and develop a more acute sense of when they’re ready.

“On average, a 100 hectoliter foudre takes 12-13 months,” confirms Woods Salazar. “It really depends on what you're going for, because you get all your acids in 4-5 months, but I like the maturity level with the big esters that happen during extended aging. Without even smelling or tasting it, if you tell me what month it is and what foudre it is, I can probably tell you if it's ready or not.”

After a foudre is used to age beer four or five times, a lot of the guessing games associated with barrel fermentation go right out the cellar window. And while the ability to calculate finite aging times might detract from the unreliable, mysterious nature of sour beer production so many brewers have grown accustomed to, the end result is almost always better.

“It doesn't exactly sound romantic when I say, 'Oh, foudre number one? She'll be ready in 10 months, guaranteed,'” Woods Salazar admits. “But I think there's art and there's science. To me, it’s a balance -- too much art and not enough science and you end up with exploding bottles. But too much science and not enough art results in lifeless liquid that isn't fun to drink.”

For brewers newer to the foudre game, it takes awhile to get used to the slower churn. But if there’s one thing American brewers love, it’s a challenge. “I think we were anticipating faster sour times,” laments Savage. “And then a year went by and we were like, ‘What the hell?’ But after a bit more research, I think we're getting there. It's always going to be a work in progress to some degree, but it's also really fun.”

At the end of the day, foudres might be tricky to learn and cumbersome to handle, but the affection and excitement Savage and Woods Salazar, as well as the rest of today’s foudre-wielding crew, have for their fleet is undeniable. The labor is real, sure -- but love always triumphs.

“My other favorite thing about foudres is that you can pet them,” adds Woods Salazar. “I always pet my foudres. It's like having a dog -- when I walk by, I just kind of give them a 'thatta girl.'”

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Note: Goose Island Beer Co. is a member of The High End, owned by Anheuser-Busch.