Ardnamushrooms

Producing the mushrooms

A short video showing how we produce the blocks and mushrooms can be viewed below

The sawdust spawn, used to inoculate the mushroom blocks, is created with a small bag of organic grain spawn produced ourselves. One bag of grain spawn can inoculate 8 bags of sterilised oak sawdust which becomes sufficiently colonised with the spawn after 2-3 weeks to be used as inoculation spawn for the fruiting blocks. One bag of sawdust spawn inoculates 12 bags of ‘fruiting’ mixture.

The bags are allowed to cool after sterilisation and then inoculated with the sawdust spawn. This happens in a special clean room that has a number of HEPA filters and positive pressure to minimise the chance of any contaminants entering the bags before they are sealed.

The bags are labelled with the inoculation date and incubated at 24oC for two weeks (for grow-your-own blocks to ensure thorough colonisation and no contamination) or two months for blocks being fruited.

Before fruiting, the shiitake blocks are taken outside for 48 hours where the colder temperature ‘shocks’ the block to get the mushrooms started. The blocks are moved into the fruiting room which has the humidity kept at 80%, there are regular air changes, the temperature is kept between 17-20oC and there is around 10 hours of bright light each day. These are optimal growing conditions for the fruiting blocks.

Once (sometimes twice) every day the mushrooms are harvested by being cut away from the blocks with a sharp knife allowing the mushroom to fall into a box. This keeps contact with the mushroom to a minimum. The best time to harvest the mushrooms is when their margin (the outer edge of the cap) breaks away from the stem. The box is labelled with the date and put into a fridge that is kept at 1-4oC.

After fruiting the blocks are allowed to ‘rest’ for 4-6 weeks when they can be re-fruited by ‘shocking’ them in cold water for 48 hours. The mushrooms start appearing about a week later.

As well as shiitake we are experimenting with oyster and Lion’s Mane which are also saprotrophs (obtaining their nutrients from non-living organic matter) mushrooms, like shiitake.