This Beer Was Only Available for One Day, and Now It's Gone Forever

It's 9 AM on a Saturday, and there are people drinking outside of Spuyten Duyvil, a Williamsburg beer bar. The bar hasn't opened yet—that won't happen until 11—but people have camped out with lawn chairs, water bottles, and coolers full of beer. These patrons, some 66 of them, are waiting in line to taste six ounces of a beer that they will never have again.

Since 2008, Belgium's Brasserie Cantillon has produced a small batch—between 3,000 and 4,000 liters—of beer called Zwanze. The word, which head brewer Jean van Roy explains as "a local type of joke here in Brussels,"doesn't refer to the style of beer: the recipe changes every year. The first Zwanze beer was brewed with rhubarb; later incarnations have used elderberry, red wine grapes, and cherries. This year's incarnation, the Wild Brussels Stout, is a Belgian take on the hearty English style: "It's dry, like a stout could be, but with sourness coming from the lambic,"van Roy explains.

The catch? Zwanze is essentially available for one day only. This year, 56 locations around the world received a single keg, which they all simultaneously tapped at 9 PM Brussels time. Aside from a few bottles that van Roy keeps at the brewery for tasting, most of the 2015 Zwanze is currently resting in the bellies and livers of beer geeks around the world. If you're reading this, it's too late. For van Roy, the constantly changing project is an opportunity to explore the imprecise world of lambic beer.

"Zwanze is, first of all for me, an experiment," van Roy says. "No one knows lambic, not even me."

Cantillon, founded in 1900, almost exclusively brews lambic beer—that is, beer made with wild yeasts and bacteria in a process called spontaneous fermentation. These brews are bracingly sour, with none of the added sugar you'll find in more accessible lambics like those produced by Lindemans, Belle-Vue, or Timmermans. That meant that in 1996, when beer distributor Shelton Brothers began importing Cantillon to the United States, the brewery was struggling to find a market, both in Europe and the States.

"This was before [Cantillon] was in demand at all,"says Christian Gregory, a Shelton Brothers employee. The company imported 20 pallets worth of beer—about 1,200 cases—which took a few years to sell. Over time, Cantillon grew in popularity. Gregory recalls that in 2010, when Cantillon announced they would temporarily suspend production of Fou'Foune, their apricot lambic, Shelton Brothers was deluged with calls from angry customers. With sour beers now back in fashion, Gregory says that demand for Cantillon has only continued to grow.

"Anything that says sour in the name is going really well these days,"Gregory says. "The Americans just seem to want more and more sour. The lower the pH, the better."

For the first few years, van Roy treated Zwanze like any other beer produced by Cantillon: a limited number of bottles were made and sold for a small fee at the brewery. But in 2010, he saw bottles being resold for as much as 80 euros online, and decided to change his approach. In 2011, the first official Zwanze Day was held, with kegs being sent out to select locations around the world.

"The idea was to work first only with friends—bar owners but friends. People I know, friends of the brewery,"van Roy says. Spuyten Duyvil, for instance, enjoys a particularly close relationship with Cantillon—the brewery made a beer named after the bar in 2005.

Since then, Zwanze Day has expanded marginally—van Roy recalls that there were only "20 or 30"locations in 2011—but not nearly enough to keep up with demand. Though Cantillon recently acquired more brewing space, van Roy says it's "totally impossible"for him to take new locations for Zwanze Day.

So is this white whale of white whales actually worth it? Is it worth traveling to one of the bars hosting Zwanze Day, or will you just find beer-bellied hipsters unwilling to admit that their emperor has no clothes?

"I don't like this,"my friend says upon first tasting the beer. "I thought you said it was a stout."

Indeed, though van Roy identifies notes of coffee, chocolate, and madeira in the Wild Brussels Stout, the casual drinker will likely only detect acidity. There's a hint of bitter coffee in the aftertaste, but this is first and foremost a sour beer. If that doesn't appeal to you, that's fine: in all likelihood, you'll never get a chance to taste it.

When the Zwanze keg is tapped at 3 PM, the vibe at Spuyten Duyvil doesn't change considerably. There's no "eureka!"moment, no one time when everyone tastes their Zwanze simultaneously. People sip the beer politely and continue what they were doing—whether that's chowing down on takeout pizza or playing a round of "Magic: The Gathering." But they're all drinking Zwanze—and for van Roy, that's what's important.

"It's always a great emotional moment, because I know that a lot of friends everywhere in the world—in North America, Scandinavia, the South of Europe—are drinking the same beer,"Van Roy says. "I didn't expect such a thing, but I'm happy that we can live such a moment with all my friends all over the world."