Rotterzwam
Rotterzwam is a Rotterdam-based mushroom company founded in 2013 with a mission to help close material loops and make the food system more circular. It grows mushrooms on local urban residual streams such as coffee grounds, brewer’s spent grain, and wood residues, then turns those mushrooms into food products and educational experiences. The company serves both consumers and business customers. On the consumer side, it sells mushroom products, grow kits, and workshops; on the B2B side, it offers coffee-ground collection, horeca and retail partnerships, and educational programs for teams, schools, and aspiring growers. Rotterzwam positions itself as a practical circular-economy actor that combines local production, transparency, and hands-on learning. Core Values Circularity : Rotterzwam’s core mission is to turn waste streams into valuable food and substrate, reducing incineration and making better use of resources. Local collaboration : The company emphasizes working locally, regionally, and internationally with partners to make mushroom production on residual streams easier and more scalable. Transparency : Rotterzwam says it shares real data about what it does and reports on its impact so stakeholders can see how materials are processed and where they go. Knowledge sharing : Education is central to the company’s approach, from workshops and master programs to open collaboration with other growers and organizations. Plant-based eating : Rotterzwam promotes a diet with more plant-based than animal protein and develops snacks and products based on mushrooms and other plant ingredients. Unique Aspects Founded around urban waste streams : Since 2013, Rotterzwam has built its model around growing mushrooms on city-based residual streams in Rotterdam, making it a visible example of urban circular food production. Measured environmental impact : The company reports that it has saved 419,840 kg of coffee grounds, grown 26,693 kg of oyster mushrooms, and avoided 144,164 kg CO2 equivalent in emissions. B Corp certified : Rotterzwam states that its impact is assessed annually through B Corp certification, reinforcing its sustainability positioning. Broad education platform : Beyond selling products, Rotterzwam has developed a substantial education offering, including workshops, guided tours, a mushroom master program, online courses, volunteering, and support for setting up new growers. Multi-region collection network : Its coffee-ground collection service is not limited to Rotterdam; the company mentions partner-supported coverage in several Dutch regions, including The Hague, Utrecht, Midden-Oost, Amsterdam, and Zuid-Oost. White-label grow kit model : Rotterzwam has adapted its grow kit for white-label use and says it works with entrepreneurs in the Netherlands, Denmark, Norway, and Spain.