Popcorn Grain Spawn

1. Soak 2.75kg of popcorn in water for 1 day. This should be enough for 10 jars and it fits in the big pot. Do this in the morning because when you start the next day it will take hours and hours and you will want to go to sleep instead of babysitting a pressure cooker.
2. Cook the popcorn for about 1 hour until it’s tender and can easily be split with your thumbnail.
3. Spread the popcorn out on cookie sheets or plastic containers to dry, about 1 hour. When you touch it, your hand should be dry afterward.
4. Put them in mason jars ⅔ full.
5. Tighten the tops of the jars hand tight and then back off a quarter turn. Cover the tops with tinfoil. Stack the jars in the pressure cooker with 3 jars worth of water and a tablespoon of vinegar.
6. Pressure cook 90 minutes at 15psi. Use the extra large burner at maximum until 15psi and then move it to the right to the normal sized burner. Leave it on high. This is the one with the broken valve so if you turn it down it may even turn itself off and the low setting is actually quite high.
7. Let them cool to room temperature, up to 24 hours, before opening. Listo.