Do not start the time until the pressure inside the cooker has reached a full 15 psi.
Grain spawn bags in pressure cooker.
If i have several small bags of grain i will pressure cook for at least 2 hours and if the pressure cooker is crammed full of large bags i ll cook for 3 hours.
It was late at night and i was sterilizing some grain in mushroom grow bags with the intention of making a whole whackload of second generation spawn.
Either of these canners will do the job.
The standard tool for the job is the all american.
Once the 90 minutes is up.
Water can be filled to half way up the jars with rags inserted into spaced to keep everything sitting upright.
Results outside of laboratory conditions may vary.
Usually making grain spawn requires the sterilisation of grains and subsequent inoculation while following aseptic technique.
Grain spawn jars can be packed into the pressure canner or instapot with a towel placed beneath to act as a cushion between the glass jars and the metal rack.
To give you an idea a bag of size 8 inches wideby 5 inches deepby 18 inches tallwill comfortably hold 5 lbs of supplemented sawdust and grain spawn.
You can just fit 6 of these bags in a presto pressure canner.
Pure mushroom mycelium added to sterilized grain has no competition which allows it to grow and proliferate throughout the grain.
You need to ensure that all of the grain gets to 121c 15psi and it can take a long time for the centre of the bags to heat up enough to kill unwanted contaminants.
You need a good quality pressure canner that can reach at least 15 psi and is large enough to fit your grain jars.
Sterilised grain spawn bags are ideal for producing grain spawn in the absence of a pressure cooker and or laminar flow hood.
Recently i managed to mess up pretty bad using my pressure cooker and i m not afraid to admit it.
I have also used the much cheaper presto canner for a long time with great results.
This is most often accomplished in a pressure cooker or autoclave by processing at 15psi for 1 5 2 5 hours.