In March of 2019 Helsieni traveled to Rääkkylä, in Eastern Finland, to meet one of the biggest Shiitake producers of Finland: Polar Shiitake. The CEO, Markku Leppänen, showed us around his business which has been growing shiitake mushrooms since 1985.
The process starts with grinding the raw material, in this case alder trees, to fine chips. The trees come from a nearby plantation. The wood is supplemented with organic wheat bran.
The substrate is then hydrated to the right moisture level and pasteurized at 70-100C for several hours in a big heater that also mixes the substrate. This same machine has a double wall that can be filled with cold water and cools the substrate.
The cool substrate is brought to a clean room, and inoculated automatically with liquid spawn from their own lab. The machine fills a plastic bag, seals it, and inoculates the liquid spawn at the same time this punctures the plastic creating breathing holes for the mycelium. The substrates are left to incubate in dark rooms for 2-4 months, depending on the demand. As the mushrooms colonize the substrate they produce heat, which is recovered and heats the whole building year-round.
After the blocks have colonized, and have turned white, the plastic is removed and they are placed in one of four fruiting rooms with rotating racks. One week later the first shiitake mushrooms can be harvested.
Polar Shiitake organic mushrooms are available in Finnish supermarkets and also exported abroad.
Polar Shiitake also sells ready to fruit mushroom substrates and ships them within Finland.
We would like to thank Markku Leppänen from Polar Shiitake for receiving us and Henri Vanhanen from the Finnish Natural Resources Institute (LUKE) for being our guide!