File this one under “things we didn’t know you could repurpose”: students and faculty at Algonquin College in Ottowa, Ontario, have created a line of soaps made from leftover animal fat. Named Dirty Duck Soap for the group’s flagship creation — a combination of duck fat, water and sodium hydroxide, a binding agent — the operation began as a way to alter and reuse waste rendered during cooking classes at the college’s School of Hospitality and Tourism. Today the organization accepts fat donations from restaurants (they never buy it) and partners with a local soapmaker that offers the facilities to keep up with growing demand for the bath amenity.

The line features nine different handmade options of animal-fat soap, priced at $4 per bar. Bestsellers include Dirty Duck, the original scent; Foul Fowl, a concoction of duck fat, lemongrass and orange; and Cafe au Confit, made from coffee grinds and pork and duck fat.

“Duck fat gives a really creamy, foamy [element] to the soap,” says David Fairbanks, chef and culinary professor at Algonquin College.

The sudsy goods are labeled with 100-percent post consumable recycled paper (to make them “as earth friendly as possible,” Fairbanks says) and sold online at Ottowans can get the duck soap at bricks-and-mortar locations such as The Red Apron, a catering and fine food company; Thyme and Again, also a caterer; and on campus at the student food kiosk.

How It’s Made

Students are involved in the process, from beginning to end, including sourcing the fat, creating scent recipes in partnership with the culinary school, and trademarking.

First, volunteer students and faculty members get the fat from restaurants — pan drippings of duck, pork and beef fat, labeled and kept separate — and boil it in water with a 3:1 ratio. Then they allow the fat to settle, draining any sediments to remove residual ingredients such as salt or rosemary.

From there the fat is taken to nearby soap manufacturer Purple Urchin. The company casts the product using the Dirty Duck team’s own recipes and allows it to cure for 30 days.

Fairbanks explains that one restaurant can render 50 liters of animal fat each month; he and his colleagues collect 100 to 120 liters of fat each month, from a handful of eateries in the area. The situation is a sustainable win-win all around: Hiring a waste management service to deal with fat renderings is a costly burden for small businesses and fat often ends up in landfills or, even worse, in sewer drains.

Redefining the Idea of Waste

Proceeds from the Dirty Duck Soap brand go to an unofficial student bursary, an emergency fund of sorts that helps pupils in need pay for things like textbooks and tools required for the culinary industry, such as knife kits and safety shoes.

Fairbanks believes the soap project is, in some ways, an answer to modern culinary trends. “Farm to fork” restaurants are everywhere, catering to consumers who want to know where their food comes from; yet people tend to show less concern for what happens to the parts of the animal we don’t eat.

“I think as a society, and this is only my personal view, we have lost connection with the farmland,” says Fairbanks. “As a result of losing [that] connection, we no longer see the value of the actual animal as it progresses through the food system.”

He gives the example of purchasing a roast chicken from the grocery store: we take it home, eat it, then throw away the bones and the fatty bits. “Nothing gets used after that, but there’s so much more you could do with it. You could bake the bones and make a chicken stock, and [when you] put that in the fridge there’s a layer of fat that develops, and that fat could be turned into soap.”

In fact, as Fairbanks points out, the amount of fat that we get from one roaster-size chicken, about 40 grams, is enough to make exactly one bar of soap.

“We’re trying to change it from a ‘waste’ perspective to a ‘usable byproduct’ perspective,” says Fairbanks. “It sounds romantic in notion, but maybe, in small ways, we’ll redefine the idea of waste.”