I decided to use 3 varieties of oyster mushrooms: King, King Blue and Pearl Oysters.
Step 1. Modification of the jars
I prepared containers for growing mycelium cakes, they are 4 oz mason jars and I drilled 4 holes with ⅛ drill bit in the cap of each, to inject mycelium liquid later. This preparation step needs to be done only once, and jars can be reused again and again.
Step 2. Preparation of the medium mix
I prepared a mix of vermiculite and brown rice flour. Vermiculite is needed for water retention and aeration of the medium , and brown rice flour is organic food for mushrooms to feed on and grow. I could have used other organic material, like sawdust but I just happened to have flour already. The exact proportions for the mix are: 7 cups of vermiculite, 2 cups of brown rice flour, and 750 ml of water.
Step 3. Filling jars with the medium
I filled jars with the mix and topped with a thin level of vermiculite which will act like bacteria and mold filter.
Step 4. Jars' sterilization process
I wrapped the jars in the foil paper to keep desired medium humidity and sterilized all the jars in my pressure cooker for 90 minutes. I am sure there will be pressure chambers available in space so the sterilization process will be much more efficient.
In total, I did 24 jars, each of them will (hopefully) grow mycelium and will be turned into mycelium cakes.
The next step is to create a sterile chamber and inoculate the jars with mycelium inside it.