Do you throw your coffee grounds in the morning with regret, for lack of knowing what to do with them? The initiative “Marc contre Pleurotes”, launched in 2011, decided to remedy the situation, thinking for years on the best way to reuse this organic waste. Until arriving at an ingenious idea: use coffee grounds to grow oyster mushrooms, a mushroom with a fan-shaped hat.
“Basically, the oyster mushroom grows on tree trunks. And since coffee is a berry, it contains cellulose, one of the constituents of wood. The two could only get along! Enthuses Arnaud Bleu, one of the co-founders of the company. After completing this unusual soil with wood chips, we add mycelium, the molecule that causes the fungus.
Subsequently, conditions worthy of the most beautiful undergrowth are recreated in a cellar in the Yvelines, and a few weeks later, you can enjoy a pan of oyster mushrooms with cream. To ensure its supply of substrate, the company has entered into a partnership with various companies and coffee shops, and collects coffee grounds per kilogram each week. Once the oyster mushrooms have grown, they are distributed to these same establishments and sold in supermarkets. And the result of this gathering is far from anecdotal since more than two tonnes of oyster mushrooms are thus cultivated each month.
A big sponge
If you are not a mushroom lover, coffee grounds have other uses. "Because it contains nitrogen and good nutrients, it will improve your compost," says Arnaud Bleu. “On a microscopic scale, it is a kind of sponge with cells full of air: a garden of Eden for earthworms and bacteria. The life of your compost will be boosted, ”he says. If you don't have a composter, use the coffee grounds directly as a fertilizer on your plants. Be careful not to abuse it however because it is very nourishing: a thin layer of 2 cm will suffice. Little more significant, polyphenol, responsible for the odors of coffee grounds, will ward off pests, such as slugs or midges, and protect your plantations.
A good air freshener
Coffee grounds also have a real deodorant effect. "Cell networks will trap certain odors," explains the entrepreneur. In your composter, it will reduce the annoying smells that are sometimes characteristic of the latter. It is also possible to place a bowl in your fridge: bad smells coming out of it will be neutralized.
Le Parisien, partner of the consultation "How to act together now for the environment?" ”, Initiated by Make.org, invites you to vote on the proposals made by Internet users in the module below. You will be informed of the results in February.