Yeast from rare butterfly harvested to brew fundraising beer

A unique beer is being brewed in Guelph, Ont., with the help of an endangered butterfly that has recently made a comeback.

Butterflies and their host plants swabbed for samples of beer ingredient

A can of beer in front of green plants at the butterfly conservatory.
The Duskywing Witbier from Fixed Gear Brewery in Guelph, Ont., is made using yeast collected from endangered butterflies. 'Flying off the shelves,' jokes brewer. (Josette Lafleur/CBC)

A new beer is brewing up interest in an endangered butterfly.

Up until last year, the Mottled Duskywing butterfly had been missing from parks in southwestern Ontario for 30 years. The rare butterfly was recently reintroduced to Pinery Provincial Park thanks to the work of the Ontario Butterfly Species at Risk Recovery Team.

To help raise awareness about the butterfly,  Adrienne Brewster, executive director and curator of the Cambridge Butterfly Conservatory, posed the idea of creating a beer made from wild yeast cultivated from the Duskywing's body.

Brewster reached out to long-time collaborator Mike Oosterveld, owner of Fixed Gear Brewing in Guelph.

A black and brown butterfly with a blue tag on its wing seen on leaves of a plant.
The Mottled Duskywing butterfly, about the size of a 25 cent coin, was almost gone from Ontario. The butterfly relies on a now-rare habitat called Oak Savanna. (Supplied by Jessica Linton)

The butterfly enjoys food that has been fermented, and Oosterveld has been supplying the conservatory with leftover fermented beer for them to feast on. 

"One day we were talking and I just mentioned my idea to consider a collaboration on the endangered species and consider harvesting the yeast from the butterfly. And immediately his eyes lit up." Brewster said.

Adrienne Brewster is the executive director and curator of the Cambridge Butterfly Conservatory. (Josette Lafleur/CBC News)

From that cocoon of an idea, emerged the Duskywing Witbier: a light, hazy beer with notes of fruit blossom.

Oosterveld says the resulting brew "aligns well for pairing with food such as salads and things like that, picnics and or backyard barbecues."

Harvesting yeast from butterflies

Oosterveld says the yeast was collected using Q-tip like swabs. With the help from a team at Escarpment Labs, also in Guelph, they were able to gather yeast from the butterflies and its host plants, the New Jersey Tea and Prairie Redroot.

"They went into the cages where the dusky wing was located. From the butterflies and the native plants, they used the samplings to start cultivating the yeast," he said.

It took head brewer Isaac Bauman about four trial runs before Fixed Gear was happy with the taste of the Duskywing Witbier. 

Fixed Gear owner Mike Oosterveld (centre) with head brewer Isaac Bauman (left) and manager Mallory Cross-Khis (right). (Submitted by Mike Oosterveld)

Since releasing the first brew last month, Oosterveld says it's been a big hit in the community. The brewery sold out of cans within weeks.

"I think that it really struck a chord. We had a lot of tours coming in. It's a great story to talk about," he said.

Partial proceeds from the sales go to the Ontario Butterfly Species At Risk Recovery Team.

Work to get the butterflies off the endangered list is expected to continue for the next five to 10 years.

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