How to use a pressure cooker for magic mushroom substrate

Growing magic mushrooms from a grow kit is easy, but to become a real mycologist you must take your mushroom cultivation skills to the next level. I do not mean a level 5 trip ;)  But making your own substrate and inoculate it with spores. For this you will need to master the skill of sterilization.

The best way to sterilize any cultivation product is in a pressure cooker. If you have one use it! In this post you find a step by step guide how to use a pressure cooker, in short a PC. General advise: read the instructions that come with the PC first.  Which materials need sterilization you can read in the blog post  The Sterilization and disinfection of Mushroom cultivation materials.

In this example I' am going to sterilize jars with substrate PF tek style. You can read how to make PF-Tek substrate in the PF-Tek instruction guide. But you can make the PF substrate when you mix 2 parts of Vermiculite and 1 part of brown rice flour with 1 part of water.

Pressure cooker guide

First thing to do is clean the Pressure cooker very good. Use anti bacterial soap or better fill the PC up with some water and let it cook under pressure for 15-20 minutes. This  will clean the PC for sure.

1) Fill the pressure cooker with 1 inch or 2,5 cm of cold water.  Make sure there is enough water in the PC that  the PC doesn't run dry during the process.

magic mushroom substrate jars ready for sterilization in pressure cooker

2) Place the rack in the PC. Put the jars on top of the rack.

If you do not have a rack you can use the lids of the jars. This must be done to prevent contact between the jars and the PC which will possibly break the glass.

3) Close the pressure cooker. Make sure the lid is closed properly.  Most PC come with a closing mechanism.

4) Get the PC to build up pressure by slowly heating it.

5) When the pressure cooker is on 15 psi let it do is job for 45 minutes

6) Turn of the heat and wait for the jars to cool down. This can take up to 5 hours

7) The substrate Jars are sterilized!

The same you can do with other cultivation materials. Make sure they can take the heat!

When it comes to sterilization your mushroom cultivation products there is one rule: Make sure to do it right! Things are either not sterile or they are!

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