How oyster mushrooms are made - materials needed with 9 steps from beginning till harvest times

Step 1: MaterialsShow more

You will need...
Straw (the medium for growing the mushrooms in)
Containers (for soaking straw)
Plastic bags (or reusable containers for holding straw)
Elastic bands or string (to constrict bag opening)
Cotton wool (to filter out contaminants)
Barrel or drum (for pasterizing the straw)
Material liner (for holding bags within barrel)
Gas burner (for heating barrel)
Bleach spray (to clean growing room)
Spoon, gloves, clean clothes, face mask (to look the part when inoculating straw)
A growing area that can retain moisture in the air, shaded with some light
Possibly plastic sheeting (to help retain humidity & to reduce other unwanted moulds)
Mushroom spawn
A water or weed sprayer (to increase humidity within growing room)
A thermometer and hygrometer (to keep an eye on temperature and relative humidity)

Step 2: Soak Straw, Drain and Bag
The mushrooms require a medium to grow in, in this case we will be using straw. The straw length should be approximately 5-10 cm (2-4 inches). Placing the straw in water tight containers, submerge the straw in water for 24 hours. Wash, rinse and drain thoroughly, then bag in 5 liters plastic bags ready for rasterising.

Step 3: Pasteurise
Position your drum onto the heat source (we used a gas burner), pouring around 40 litres of water into the drum. Place a suitable platform at the bottom of the drum, one that will keep the bags above the water yet allow steam to rise. Insert a material bin liner and fill with the prepared bags of straw. Close off the bags with the liner and cover the drum with a lid. Heat the drum, steaming the bags for approximately 60 minutes. It should take around 30 minutes for the steam to make its way to the top bags (the temperature should near 95°C ~200°F). Leave to cool, removing the bags and transferring them to the growing area.

Step 4: Prepare Growing Room
The growing room should be clean and dimly lit (shaded with indirect sunlight), able to retain moisture in the air yet also provide an airflow when ventilation is needed. Plastic sheeting can be used to seal off an area to help retain humidity and to reduce other unwanted moulds and insects.

Step 5: Inoculate Bags
Before inoculating the bags of straw, make sure you have showered and are wearing clean clothes. Clean your hands with antibacterial soap or wear sterile gloves. A face mask and hair cap will also help reduce contamination (we are very dirty creatures).

Open the bags of straw and the mushroom spawn. Taking a sterile spoon, place a few spoonfuls into the straw, breaking it up and mixing lightly. As a general rule, the more spawn you add, the faster the substrate will be colonized (with 1 liter of spawn, we inoculated about 10 bags - you could inoculate more).

Restrict the opening of the bag by placing a rubber band (or cord) around the bag's neck. Taking a small piece of cotton wool, plug the bag's opening to reduce the chances of contamination and insect infestation. Leave to incubate.

Step 6: Encourage Colonization
Once inoculated, the bags should be left to incubate. During this time the spawn "runs" (mycelium spreads) throughout the straw. The spawn run will be complete when the mycelium has spread entirely throughout the bag (the straw is then fully colonized).

Depending on the mushroom variety, humidity and temperature, this process should take between 1 to 3 weeks.

Step 7: Monitor Bags
It is important to monitor the bags for any sign of unwanted moulds and pests. While the straw is still in the bags, you shouldn't have a problem with insects or mice. However, the best policy for fighting both contamination and infestation, is prevention. You may want to spray some surfaces to deter flies and other insects from setting up home, mesh any windows and keep doors closed.

Step 8: Encourage Pinning
Once pinning has started, it is time to remove the substrate from the bags. Pinning naturally occurs as humidity increases, low levels of light appear and temperature levels fall. Increase the growing room humidity by regularly spraying with a water sprayer (avoid spraying directly on the mushrooms). You can also wet the floor and leave open containers of water in the room (95-100% humidity is recommended). As our climate is very dry, we only managed 60% at best, dropping down to 40%, by spraying 5 liters of water 2 - 3 times a day (even at these humidity levels a good result can be achieved). To prevent excessive CO2 levels, allow the growing area to flush with clean air before spraying. If you can, regulate the temperature accordingly.

Step 9: Harvesting
As the mushrooms begin fruiting, it is important to keep the humidity high (85-90% is recommended). As before, allow air to flush through the growing area prior to spraying (oyster mushrooms require a consistent source of fresh air). Temperatures can now be higher than for the initial pinning stage.

Now, finally take your harvested mushrooms and create a delicious mushroom meal. Enjoy.