While leading an edible plant walk in Cohasset a couple of years ago, Russ Cohen, an environmentalist for the Massachusetts Department of Fish and Game, fielded a question about brewing beer with rhubarb. Cohen, author of “Wild Plants I Have Known . . . and Eaten,” thought for a second and replied, “If there’s a rhubarb beer there should be a knotweed beer.”
The questioner was Kristen Sykes, founder of the Boston Area Beer Enthusiasts Society (BABES) group and an avid homebrewer. Sykes had read Andy Hamilton’s book “Booze for Free” and wondered what ingredients, foraged from near Holly Hill Farm where she lived, would work well in a beer recipe.
On the surface, Cohen’s suggestion of Japanese knotweed (Fallopia japonica) seemed like an odd choice. Native to Japan, China, and Korea, the plant is ubiquitous in New England in the spring. It’s also an invasive species, usurping the habitat of native plants, especially along rivers in Northern New England. One of the goals of environmentalists like Cohen is to eradicate this large, herbaceous perennial, but there’s a lot of it. Recently, truckloads of the plant were hauled from a piece of conservation land in Rockport.
Last year, Sykes put knotweed to the test, brewing a batch of beer with a natural tartness from the plant with rhubarb-like qualities. She let both beer-industry and environmental friends try some out.
“The tartness doesn’t hit you right away,” says Sykes. “It’s very good and kind of surprising. It’s really educational for people to see that a pernicious weed, something that people are trying to get rid of, is being used to brew beer.”
“Usually I hate beer,” says Cohen. “But I liked this.”
Sykes recently brought the idea for a knotweed beer, along with 25 pounds of the plant harvested from the banks of the Connecticut River, to Cambridge Brewing Company, where brewmaster Will Meyers tweaked the recipe and scaled it up for consumption on the premises. The pair brewed a batch of the beer, modeled after a German Berliner Weisse, two weeks ago. The recipe is similar to Sykes’s original but tweaked to be less malty, providing a base that is “light, dry, and refreshing, one that would benefit from splash of tartness,” according to Meyers.
Working with something as exotic as knotweed presented Meyers with a challenge. The plant “has a vegetal character that does dissipate with time.” Meyers and Sykes used 1.4 pounds of knotweed per barrel (the plant was put in a kind of mesh cage so as not to clog up the brewing system) and brewed a tea with another 10 pounds, infusing that into the beer. Cranberries were eventually added to the brew to give it an extra kick of tartness and add some fruity character.
“I got to see what it’s like when you try to puzzle out how you make a recipe,” says Sykes.
That puzzling is what early New England settlers used to do when making beer with ingredients they foraged locally. The knotweed beer and some of the Gruit-style beers Meyers makes at Cambridge Brewing get their flavor predominantly from herbs like lavender, yarrow, and mugwort rather than bitter hops. Knotweed and other plants were much more available to early New Englanders, so brewing with them now is a bit of a blast from the past.
“I think the utilitarian-ness of it is really cool,” says Sykes. “It’s quintessential New England.”
Cohen, the conservationist, says he’d like to see more brewers use foraged ingredients as a benefit to both the brewer, who would obtain free raw materials, and the environment.
Meyers named the beer Olmstead’s Folly, after Frederick Law Olmstead, the architect responsible for Boston’s Emerald Necklace. Olmstead is credited for having introduced Japanese knotweed to the United States. Cambridge Brewing puts its first-ever knotweed beer on tap Friday.
99 Bottles Twitter Tasting
Join me next Wednesday, at 8 p.m. as we compare tasting notes in our weekly 99 Bottles Twitter Tasting. This week’s brew is Harpoon’s UFO Big Squeeze Shandy, a beer brewed with fresh grapefruit juice that is perfect for summer sipping. Grab some and join in by using the hashtag #99Bottles. Even if you don’t have the beer, you can log on and add to the conversation. More details on the tastings can be found at www.bostonglobe.com/99Bottles.