When drinking beer and being awestruck at the brewing process, nobody ever wants to imagine the random chance at foreign organisms bombarding the brew. But when the wort’s kicking it in a koelschip (coolship), it’s bound to happen.
And the Portland, Maine, Allagash Brewery outfit are no strangers to such obscene occurrences—they do around 10 koelschips ales a year. It’s not like this wort cooling can be done anytime—a small spot during winter. To succeed at this suds, the temperature has to be so low a brew isn’t beckoning microbes and wild yeast to drop by.
If done correctly, artisan alers would bask in about 300 barrels of either Belgian-inspired lambic or the even-more-specific gueuze-style blend (up-to-three-year-old lambics). With those fond foams in mind, only one American brewery can toot trail-blazer status—again, Allagash. Their cherry-aged Coolship Cerise and Coolship Resurgam are quite the koel concepts.
It was 2008 when Allagash was enacted as the first, American, commercial crafters to burgeon a koelschip. A trek to Belgium was in the cards for those who craved this style in earlier years. Brussels’ Brasserie Cantillon is certainly among Belgian brewers who’ve been stewing up suds in exposed vats for hundreds of years (Cantillon Est. 1900).
Upon Allagash and Belgian brewmasters tailoring the tradition to American mouthpieces, around 24 breweries have jumped on the koelschip bandwagon. Now, this trend’s taking the US by storm—American-coolship style.
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“Many brewers are interested in beers that are uniquely tied to time and place, and 100-percent spontaneous fermentation is a great way to go about this,” Jester King Brewery Founder Jeffrey Stuffing explained in an interview. His Austin-based brewery is infamous for wild ales and comes in first in terms of a large flow of US coolship-brewed beer.
Oxford’s OEC Brewing Assistant Brewer Dave Linari concurred. “It adds to our house terroir,” Linari said about their coolship—part of a winemaker’s repertoire and normally reserved for referencing the climate, soil and other elements that go into flavor and aroma. “Wild fermentation also allows for more creativity than clean-fermentation techniques and opens up a world of flavors and aromas,” he added. The coolship process enables beer to acquire complexities while aging, grabbing flavors from the barrel’s remnants of previous liquids, merging with microorganisms in the wood, oxidizing at a slow rate.
Coolships are rather easy implementations—cleaning’s quick too—but this process requires much time and tending to. (Air+beer can equal bad news.) However, it’s all worth it in terms of personal achievement for coolshippers. Believe it or not, many gravitate toward this technique over the quick-and-penny-pinching kettle souring. “In my experience, there’s just no shortcut when it comes to creating the complexity you get from spontaneous fermentation with wild yeast and bacteria,” Stuffings elaborated. “The difference in flavor, aroma, mouthfeel is night and day.”
If interested or a proponent of this beer, check out the step-by-step journey at Allagash. Their team immerses themselves into a system of combining and heating grain—from mash to the point of beer barreled for aging.