The Ghost & the Gourd: Allagash Ghoulschip Is Brewed on Halloween

By David Nilsen

Lifeforms we can’t see float through the air around us. They move among us, we breathe them in, and most of the time, we have no idea they’re there. No, I’m not talking about ghosts; I’m talking about the countless microorganisms—fungi, bacteria—that cover nearly every surface around us, including our skin, and get carried on air currents to what they might hope will be their next meal. 

In a small room at Allagash Brewing Company in Portland, Maine, that next meal might be cooling wort straight from the brewery’s boil kettle. Each year on All Hallows Eve, that wort will be laden with the essence of crushed pumpkins and molasses, and the invisible lifeforms haunting the Allagash coolship (koelschip in Flemish) room will descend upon a steaming seasonal liquid to make their contribution to one of the most unusual pumpkin beers in the country.

Allagash Ghoulschip is a 7.0% ABV sour ale brewed only once each year. After cooling in the coolship overnight, the beer is sent to a conventional stainless steel fermenter where the brewery’s house yeast—used for classics like White and Tripel—is pitched. After fermentation, the beer is then aged in barrels for one to two years before being blended and bottled.

A coolship is a wide, shallow, open metal basin used for cooling boiled wort. The vessel is well-known for its use in the Belgian Lambic tradition, though it has been used for brewing many other styles over the years. In Lambic brewing, it was long held that the microorganisms that give those beers their notable acidity and funkiness were collected from the air during the beer’s overnight rest in a coolship. While this undoubtedly contributes to the microbial load of the beer, it is now assumed most of the microbes that ferment these beers are resident to the wood of the barrels used in aging them. 

Brett Willis, who handles media and communications for Allagash, says the brewery looks to the ambient microorganisms in the air of the coolship room and the wooden barrels the beer ages in to provide tartness, but the house yeast does the heavy lifting.

“When you think spontaneously fermented beer, you think of the barnyard, the funk, that sort of thing,” he says. “You're getting less of that [in Ghoulschip] because I think the house yeast is doing a lot more work and you're getting more of a nice, clean tartness with just a little more going on.”

The beer is brewed with a hefty amount of fresh pumpkin flesh, toasted pumpkin seeds, and molasses, all added during the mash. The Allagash brewers aren’t sure exactly how to describe the impact of these ingredients on the finished flavor of Ghoulschip, as it’s not a typical “pumpkin spice” beer. They note butterscotch, frosting, and burnt sugar are all common descriptors, even though it isn’t sweet.

“If you've ever tasted it, it's not pumpkin,” says Willis. “The pumpkin adds some roundness of flavor to it, but it's just a cool, nuanced beer where if you didn't tell someone pumpkin was in it, I don't think they'd ever be able to pick it out and say, ‘oh, this is a pumpkin beer.’”

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The morning of October 31, the Allagash team assembles to crush the pumpkins for the beer—350 pounds worth. They use a device that will chip and grind the flesh, but the pumpkins themselves have to be smashed first, and the crew uses baseball bats or whatever other implements are handy to crush the gourds.

“It's one of those traditions that I think is pretty universally loved,” Willis tells me. “It's fun to crush up the pumpkins. It is definitely cemented as a tradition and a thing that is pretty universally enjoyed here at the brewery. There's not been a single year that we've missed putting it out on Halloween night.”

After the mash and the boil are finished, the hot wort streams into the coolship and fills the room with steam as windows along the walls let in the chilly autumn air. As the liquid cools, the spirits of microscopic life descend upon it.

“It stays out in the coolship over Halloween night, so you get the specters and things in there,” says Willis, aware of the romance that pervades this storytelling. “I think that's kind of the fun part for me—the idea behind it is a bit gimmicky, but then the resulting beer is actually just a really nice beer that if you didn't put Ghoulschip on it, if you branded it something totally different and served it as at a nice dinner party, people would be like, ‘oh wow, there's something really going on here.’”

While most of Allagash’s labels are gracefully designed to convey the elegance of the brand and its beers, Ghoulschip’s label is more silly and fanciful. It’s handdrawn and shows a friendly ghost coming in through the windows of the coolship room and floating over the beer in the open vessel below. It’s  just a colorless sketch—Willis says someone at the brewery drew it, though he’s not sure who—but it conveys the sense of whimsy and fun the beer represents for Allagash. Craft beer is an often fraught and stressful business, and it can take itself too seriously. Ghoulschip is a reminder that even at one of the most respected breweries in the country, sometimes you just have to have cut loose, smash some pumpkins, and revel in the spirit of the season.

As you go to bed Halloween night, know a future batch of Ghoulschip is doing the same.

All images provided by Allagash Brewing Company.