Well I'm just a week or so ahead of you with my shroom growing experience. I also used a pressure cooker with half pint jars, and the best thing I can tell you is that you don't need as much water as you may think. Just like Shapipe said about 1/5 of the way up the jars would be plenty, cause all you need is enough water in there to generate the steam that is what actually does the sterilizing, not the water.Anyways one more thing, when your jars come out of the pressure cooker, they'll probably look darker than they were before, and also it may look like they're really wet. Don't worry about it, they'll be fine. I freaked out when mine came out like that, and right now I've got half my jars 75-90% colonized, and it's only been 9 days since I innoculated.
Oh yeah and remember to run a lighter across the needle of the syringe between innoculating each jar, that's very important. Good luck.
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