Helsieni visits RotterZwam

We reached another milestone with Helsieni: we graduated from the Master Program: “Growing Edible Mushrooms”! The founders of RotterZwam in the Netherlands offer an intensive 4-day training program in which Sini and Stéphane learned everything there is to know about growing mushrooms in an urban environment. Chris and Lilli also joined the beginning and the end of the program, and in the evenings we discussed until deep in the night about all the things we had learned.


For four days we were running the mushroom farm. The week starts with picking up coffee waste from the partner cafe’s or offices.  Stéphane took a ride on the custom-made coffee collection cargo-bike. (We might need an E-bike to be able to cross Helsinki with 100+ kilos of coffee waste, though).


We learned about making the ‘magic mix’ substrate bags. A perfect combination of coffee, filler and mushroom spawn, in order for the mushrooms to grow optimally. Sini paid special attention to how the room needs to be organized and climatized. There are two specific environments necessary for mushroom farming: a growing room and a fruiting room, both with specific conditioning requirements.

Huge-Oyster-mushroomsFinally we learned when to harvest and how to prepare them. we even tasted the world-famous in Rotterdam delicacy: the Oesterzwam bitterbal. This is a deep-fried ball of oyster mushroom ragout, covered in breadcrumbs. Delicious!

On the final day we discussed all the Ins and Outs of running an urban mushroom farm, covering finances, business models and how we can contribute to the growing european network of urban mushroom farms.

All in all an exciting week, thank you RotterZwam!