Blackbelly Leads Sustainability in Boulder, Colorado

As a chef dedicated to the farm-to-table movement, Hosea Rosenberg thought it would be a great idea to raise his own animals when the opportunity arose about a decade ago. He quickly learned that he’s a better chef and restaurateur than farmer, among other lessons. He also came away with the conviction that waste reduction is imperative to the farmer-chef relationship. “Once you put this into practice, spend time on a farm, raise an animal yourself, you understand all the resources that go into it, and it’s painful to see anything go into the trash,” he says. So he does all he can to minimize waste.

Rosenberg is the owner of Blackbelly, a catering operation, restaurant, and market in Denver and Boulder, Colorado, that has been recognized by the Michelin Guide and Slow Food USA as one of the country’s most sustainable eateries. Waste reduction is key and goes beyond recycling to minimal packaging on-site and with partners. The restaurant’s cooking-oil supplier reuses its containers; the microgreens producer reuses its plastic trays. “It’s almost impossible to have no trash coming out of the restaurant when you’re buying from purveyors that use packaging, but the less the better,” says Rosenberg. “We encourage people we work with to lower their impact.”

Minimizing food waste

Blackbelly’s market features a bakery focused on whole, local grains as well as Boulder’s only whole-animal butcher shop and charcuterie producer, a natural evolution given Rosenberg’s respect for the farming community. “Knowing the rancher, buying one at a time, respecting the lives of both, we find it’s important to use every last piece,” he says.

The nose-to-tail approach leads to wide-ranging applications. Many premium cuts of beef or lamb go straight to the butcher case. Others go to Blackbelly’s dinner menu along with lesser-known cuts, “and then we get creative with the rest of it,” says Rosenberg. The bones become stock sold in the market or turned into soups. Offal enhances terrines and sausages. Marrow bones and bits of pig skin become dog treats. “You name it, there’s some process involved — we try to make sure nothing ends up in the garbage.”

The same goes for produce, some of which is grown in gardens on-site. “We have some amazing produce in Colorado, but the growing season is short, so we’ve honed in on preservation techniques like fermentation and dehydration over the years,” he says. As end-of-season frost approaches and farmers price bulk tomatoes to move quickly, Blackbelly turns a huge amount of them into tomato sauce that gets vacuum-sealed and frozen. Bountiful herb harvests become oils, pastes, and powders to last throughout the winter. Pickling and fermentation coax new flavors and textures out of fresh ingredients even as they lengthen shelf-life, processes the team recently practiced in a training lab led by Mara King, director of fermentation and sustainability at like-minded Colorado hospitality group Id Est. “It’s ramp season now, so we’re serving fresh ramps with pickled ramps from last season,” says Rosenberg. “It’s really fun.”

How restaurants can be more sustainable

Compost is key for keeping organic matter out of landfills, but Rosenberg suggests any restaurant trying to reduce its food waste “start with things that would normally go in the trash or compost and try to rethink it.” It can be as simple and obvious as prepping daily staff meals with trim like potato peels and bread crumbs made from stale bread. At Blackbelly, a string of fish bones dangles above the grill, smoked and dehydrated for a flavorful stock. Herbs and flowers from last year’s garden hang all over the kitchen, some for food, some just for beautifying the space. Beautiful greens atop farm-fresh carrots don’t need to be composted when they get turned into a condiment like carrot-top pesto or gremolata for serving with the carrots. It’s all about telling a story on the plate, Rosenberg says, and “it all saves money and waste.”

Another example of repurposed waste that became a signature is Blackbelly’s spread for the bread service, which originated when a carrot in the oven went from dehydrated to burnt. Instead of immediately composting the blackened vegetable, the team ground the ash with Maldon sea salt and mixed it with butter.

“We get more compliments on our bread and butter than anything, and I think a lot of that is due to that jet-black, umami, smoky salt,” he says. Now the restaurant makes the vegetable ash intentionally with whatever peelings and tops from carrots, onions, and celery don’t go into stock, serving the ash salt in the restaurant and selling it at the market.

“Our bread is really good. We make it fresh with local, organic grains, milled right before we bake. But people can’t believe how good the butter is,” Rosenberg says. “Bob Ross would say there are no mistakes, just happy accidents. Something that might seem like a disaster could turn into something magical.”