[CH] need help w/ pressure cooker (aka poor man's autoclave)

Jim Graham (spooky130u@gmail.com)
Tue, 9 Jun 2009 14:41:28 -0500 

I've just bought a medium-sized (8 qt) pressure cooker for sterilizing.
Its pressure regulator works at 15 PSI, which I every source I have read
or talked to has said is correct for that magic temperature, 250 deg F
(121 deg C).

I have two primary uses in mind.  The first use is sterilizing culture
media for brewing yeast, mostly for making 10 mL starters---I bought
autoclavable tubes and caps from Cynmar Scientific for these.  Along
with that, I'll also be using it for making and sterilizing new agar
plates when the ones I bought are all used up.  I have 600 mL beakers
(also from Cynmar) for putting the starter tubes (and plates, when I
get to that point) into.  The beakers are also autoclavable.

The second use that I have in mind is for sterilizing bottles of hot
sauce the next time I make some (that way I don't have to rely on the
pH being low enough).

Ok, here's what I THINK I need to do....

If I understand correctly, I open (just slightly) the containers that
I'm sterilizing...both to vent, and to expose the contents to the steam.
Then I put those into the beakers, PUT SOME UNKNOWN AMOUNT OF WATER
(need help here for sure) in the bottom of the pressure cooker (oh,
and the rack is assumed to be in there, too).

Then, (again, as I understand it), I seal it up, put the rocker on top,
and turn the stove way up and let it rock.  When the rocker starts
going like a bat outta hell, start a 20 minute timer, and after 20,
remove it from the burner.  After the pressure is released, I open it
up (no air movement allowed in the kitchen while I'm doing this---I
know that much from culturing yeast in general) and tighten all of the
caps and put the tubes into the test tube rack.

Does that all sound about right?  What amount of water should I use?
Am I missing anything?

Thanks,
   --jim

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