I know, growing mushrooms sounds really bonkers, but after seeing so many DIY sets, I really wanted to try it out for myself. Turns out, I’ve already harvested 400 grams of beautiful Grey Oyster Mushrooms. And to imagine that the only thing I did was drink coffee (!). Which basically means that all my coffee drinking finally feels productive.
I’m writing this post as I had doubts myself before starting this little project, and figured that more people would be happy to read about it.
The general idea of the mushroom sets available is that you get a starter (the internet tells me that this is called the ‘spawn’ in mushroom-terms), that you then mix with fresh and moist coffee grounds.
The coffee grounds are nutritious enough for the mushrooms to grow on them, which means that you don’t have to add anything else than the remains of your daily cup of coffee.
The set I ordered came from a Dutch company (Rotterzwam), and was delivered in a little plastic bucket with holes on the sides covered with breathable tape, but there are many different suppliers out there (even with different kind of mushrooms).
According to their instruction videos you need to limit the risk of other bacteria taking over, by boiling out (meaning: pouring in boiling water, letting it sit, pour it out and let it dry in the air as you would with canning jars) the coffee ground compartment of your coffee machine as well as the plastic bucket in which the mushrooms will grow.
Once all is clean, you mix the ‘mushroom starter’ with coffee grounds and pour it in the bucket, that you then close. Now you wait until a white layer forms over the coffee grounds (I found that this took a little long, let’s say a couple of days). Only after this white layer has formed, you’re supposed to add more coffee grounds (without having to mix anything). You repeat this process until your bucket is completely full with coffee grounds turned white. Once you are at this stage, you can take off the tape (!) and wait for mushrooms to grow out of the kit. These are grey oyster mushrooms, which grow better in the cold, and I have therefore put them outside (in winter) when I wanted them to grow. Other types of mushrooms might need different temperatures. After seeing some instruction videos, I’ve discovered that adding more (boiled) water to coffee grounds before adding them to the bucket makes the undertaking more succesfull.
And what makes all of this even more exciting: you can revamp this kit by taking out 80 percent of what is left in the bucket after your harvest, or when nothing grows out of the kit anymore, and start all over again with 20% of the content of your bucket, by mixing it again with coffee grounds. As a little note: before restarting the kit, I have cleaned out everything again as, which I am not sure is necessary, but did make me feel more comfortable about the result.
In any case: I couldn’t be more proud of this modest harvest and can only highly encourage you to try yourself, especially in winter you will notice that the set will flourish in the cold. Also: enough reason to make some Stuffed Mushrooms, Mushroom Flan or a simple Bread Pudding. Have a nice evening!