Chances are high you are reading this from a beach chair in France or with your feet dangling off the border of a swimming pool in Italy. Or maybe you are sipping from a coffee on la Rambla in Barcelona? While coffee ground is usually thrown away, some creative souls have found a better purpose: to use it for growing mushrooms.

The people I am talking about are from Permafungi, a small business in my home base Brussels. Of all¬†sustainable projects to be discovered in the Belgian capital, they are definitely one of my favourites. And you will soon see why. For me, it represents all that I like about the city: a bit rebellious, doing things differently, and making the best of what one has. With respect for nature, and with the passion to make a supreme end product. Let’s see how it works.

Bags are filled with a mixture of coffee ground, straw, and mycelium under sterile conditions (photo: Permafungi)

Permafungi is growing food from food waste. They collect about one tonne of coffee ground every week from the tredy Exki and Pain Quotidien restaurants around the city. Pickup is done by cargo bike couriers, no cars or trucks involved here! The coffee ground is mixed with straw and mycelium, the seeds of mushrooms. Preparation happens under a sterile environment in the basement of a reclaimed industrial building that once was the customs office for packages arriving in Brussels, before the unified EU customs zone made it superfluous.

The mixture is placed in large bags and hung in a dark room with a controlled temperature. During the next three weeks, the mycelium starts ‘eating’ the substrate of coffee ground and straw. The bags turn from black to white, due to the dense root network that is being formed. Still no sign of mushrooms though.

What is missing? The libido. Yes, the libido. Mushrooms are the genital organs of mycelium and to get things uuuhm… going, one needs to give the right stimuli. The bags switch environment and are now placed in a light, cold room with a very high humidity. You see, for mushrooms, it goes better if they are wet (pun intended).

In the second stage the mycelium starts forming a dense network, turning the content of the bags white (photo: Permafungi)

Every day, the mushrooms double in size and after a week they are ready for harvest. In total, Permafungi can repeat this cycle twice more. Afterwards, it is time to remove the bags and… don’t throw them away. Nothing is wasted: the mycelium has turned the coffee ground in a nitrogen-rich soil that is now perfectly suited to grow chicory, one of Belgium’s finest vegetables. Since chicory needs a warm environment in the second stage of its growth, the heat that is removed from the mushroom room finds a useful purpose.

The result: organic, tasty mushrooms. Found in all good food markets around Brussels (photo: Permafungi)

The final produce is distributed in food markets and restaurants around the city, by the same bike couriers that pick up the coffee ground with which the whole circle started. Driven by an enthusiastic team that has adopted the cooperative model to run this small company, Permafungi keeps looking for ways to reuse all material flows. A lamp hood made out of condensed and dried mycelium may sound like a weird idea, but it is definitely more original and sustainable than getting one at IKEA.

Did you ever hear a better example of the circular economy? I didn’t, and I am very proud Permafungi is based in my city!

PS: If you would like to try to grow some mushrooms yourself, you can order a DIY kit from the Permafungi website (only in French and Dutch).