GRO-Holland uses coffee residue as a growth substrate for oyster mushrooms, which it sells back to the cafes that provide the coffee residue, thus inhabiting a unique niche in the distribution network. Source: www.gro-holland.com
Coffee grounds, 2500 kilograms per week, are dropped off at the facility. The coffee grounds are put through an industrial mixing machine with oyster mushroom spores, 240 kilograms per week imported from Belgium, and a natural agent that prevents compaction of the mixture. The mixture falls into tubular, finely-perforated plastic bags. The bags are hung in the incubation room during which time mycelia grow through the mixture and a large amount of heat from composting aerobic bacteria is generated, though in this pilot facility the heat is not reused. After four weeks, the bags are shocked for one day at lower temperature to activate the mushroom growth. The bags are then sliced open and hung in the fruition room. The fruition room is sensitively climate controlled to maintain warmth and humidity without disturbing the air, which must remain as still as possible. The odor from mushroom growing is strong, so an air filter is used on the exhaust from the fruition room to reduce emissions. When the mushrooms are ready, they are hand-harvested. The coffee-mycelia mixture is given to nearby tulip farmers as a soil conditioner. The mushrooms are delivered to La Place cafés across the Netherlands, where they substitute the flow of mushrooms from conventional sources.
Before the project, the coffee residue was treated as other green waste (GFT). Mushroom cultivation typically uses straw as a substrate. Mushrooms had to travel from their place of origin to a distribution center, and then be distributed to the restaurants.
Gro-Holland was the initiator of the project. When approached, La Place accepted the project idea. La Place’s sustainability goals, including natural and organic ingredients, regional ingredients where possible, and a large vegetarian menu, fit within the concept of recycling coffee waste into mushrooms.
The mushroom growing process had minor start-up complications. Time was needed to optimally set up the production facility, adapt growing techniques, and regulate temperature and humidity. Regarding investment, it was thought that 50,000 euros would be enough for the entire project, but that amount more than doubled. The income of the project is set to the market value of oyster mushrooms. Their business is slightly affected by fluctuation of the market demand for mushrooms, which changes seasonally, especially when asparagus and strawberries are in season.
In the legal and regulatory context, no legal permits are required for the relatively small size of the growing operation. In order for the growing medium (coffee grounds plus mycelia) to be used as a soil conditioner, a lab analyzed the substance for heavy metals and eutrophic nutrients, and approved the quality. Gro-Holland would consider becoming certified organic in order to add economic value to its product, though all of the coffee would need to be certified as well.
The project’s chain thinking exhibits strong symbiotic relationships. Gro-Holland implanted itself within the café chain’s existing distribution network, in which coffee residue was already being separated. The distribution trucks are full in both directions, dropping off coffee grounds and picking up mushrooms. Previously, mushroom-delivery trucks would be empty returning from the distribution center and La Place supply trucks would be empty on their way to the distribution center. Now, the pathway between the consumer and producer is bi-directionally efficient. The growing medium is connected to tulip farmers within the locality, who use the material as soil conditioner, though there is no economic value generated by the flow.
The non-optimal aspect of the Gro-Holland facility is its use of space. The growing facility is located in a rural village north of Amsterdam, whereas it could have been in an urban interior space, for example in the Netherlands' plentiful empty office space, or in a basement, as no natural light is required. Spatial optimization in an urban interior would have the double benefit of improving land use as well as decreasing transportation costs.
Gro-Holland's success shows that on a relatively small scale, organic waste streams can be utilized in mushroom cultivation. For a future implementation, considerations are energy efficiency in operations, such as reusing heat from incubation in fructification and heat exchange from outgoing air from the fructification, low rent per square meter of growing space, and optimization of geographic location.
Gro-Holland is a supply-demand matching cyclifier type. Its inputs come from a pre-existing stream of coffee residue, which previously would be treated as green waste. Its outputs are substitutive; completely replacing the import of mushrooms typically cultivated using straw as a substrate. It exists in a strong material ecological niche, using the opportunity of closing a material loop. The policy dimension is weaker, but Gro-Holland did benefit from green innovation financial awards and from the café chain’s eagerness to improve their sustainability image.