OK this is gonna be a quick oddball post, but I’m so excited about this that I can’t not tell the world.
Pandemic life has found me, like many, drinking much more coffee made at home, and also exploring new hobbies and ventures. One of these new ventures is experimenting with mushroom cultivation. There are myriad techniques at all levels of sophistication for the many varieties of edible and medicinal mushrooms, but I was instantly excited when I learned that one can grow oyster mushrooms on used coffee grounds with virtually no technical set-up.
I mean for real, cheap coffee that turns into free food?! This is like a math graduate student’s dream.
So I saved my spent coffee grounds in the freezer for a few weeks, got some oyster mushroom spawn, then inoculated the grounds in a sanitized plastic container and waited. Among cultivated mushrooms, oysters are known for being particularly vigorous and adaptable, growing on anything from logs to old clothes to coffee and tea. The rapidity with which they colonized the grounds was astounding; already the next day the mass was glowing with patches of white mycelium waking up and stretching its legs. Within a week, a fluffy cushion of the stuff coated the whole surface. A few more weeks go by (maintaining high moisture in a cool, dark place) and voila!
One day the fruiting bodies start to “pin” and then they double in size for a few more days until they are ready to harvest. The next night, mushroom fried rice for dinner. : D
As the myco-aware are eager to tell you, this is a large untapped resource that society in general and the math community in particular has been sleeping on. In our department, another graduate student used to collect used grounds from the coffee machine for compost, but with very little effort every department could put its spent theorem-precursor to good use by setting up its own mushroom growing operation (myceliated substrate makes great compost after the fact).
Growing food is a radical community-building and liberatory act. The origin of the word university is the combination of uni (one) and versus (turned), “turned into one”: basically, community. Subsidizing graduate student grocery budgets is one thing, but whenever we get back to being able to sharing pots of coffee, this would be a great project for pushing on universities to be a little more like communities and less like bureaucracies.
I basically followed the instructions here, and I recommend the source book (in the link) to anyone interested in learning more.