Oxbow Brewing Company, soon to expand with a tasting room and warehouse at 49 Washington Avenue in Portland, tested out its new coolship on Tuesday. A photo on Instagram shows the Newcastle brewers introducing hot wort (unfermented beer) to "wet," or freshly harvested, hops from The Hop Yard, which grows hop bines in Fort FairField and Gorham.
Allagash Brewing Company has helped popularize the concept of this traditional open-air tank in America. Known as a koelschip in Flemish), it's a shallow, wide container designed to efficiently cool wort without the use of a modern heat exchanger. It is typically utilized to inoculate beer with favorable wild yeasts and bacteria, leading to the production of sour beer styles. Allagash's successful introduction of this system in 2008 defied conventional wisdom, which long held that only Belgium was home to the proper kinds of microorganisms required for this manner of spontaneous fermentation.
In this case, though, Oxbow brewer Michael Fava explained that the wort was not left overnight, as no spontaneous fermentation was intended. Because the whole-leaf hops harvested from The Hop Yard take up so much space, Oxbow used its coolship and its mash tun as makeshift hopbacks, allowing the wort to pass through as many hops as possible, picking up flavor and aroma on its way to a fermentor as normal. It was still cool to see "the maiden voyage" of the coolship, Fava said, but this was a test and a "creative way to make a wet-hop beer." The beer will pour at a wet-hop event called Hoptoberfest at In'finiti Fermentation & Distillation in October.
"We have the first wild fermentation batch on the calendar for next week, weather dependent," Fava revealed. Chilly nights, which we've had a few of already, are ideal. "The point is to naturally cool the wort for yeast to thrive, and you want to find a time when good yeast fills the air," he explained. Winter is too cold, as there's too little yeast activity, and summer is too hot, which increases the likelihood of bad yeast dominating. As such, spring and fall are the best seasons for wild fermentation.
Those looking to sample a coolship beer from Oxbow will need patience, as wild fermentation can take months or years to finish. Don't expect fresh or powerful hops to be used, either. Fava said hops, with their preservative qualities, can hinder yeast activity, which means older, less viable hops are typically used in small quantities for coolship beers.
In the meantime, seek out the latest in the brewery's Freestyle series, #26, or track down Grizacca if it's still around. Last month, beer writer Josh M. Bernstein called it one of ten Belgian beers you should be drinking right now. "Oxbow kills it with saisons, sour ales, and other funky fermentations," Bernstein avows in the piece for Bon Appétit. And expect the tasting room to open "before the end of the year, definitely," Fava promised.
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