Pressure Cooker 101

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By Nanook of the North (Nanook) on Monday, August 06, 2001 - 12:28 am:

Pressure Cooker 101

Check the seals and safety fuse.

Place STANDOFF PLATE on the bottom

Fill with jars FOIL COVERS ON!

Add DISTILLED WATER to halfway up the glass on a 1/2 pint widemouth jar (about 1 inch)

Place on the lid, locking the seal.

Heat on high until water boils and steam is venting... Then close the valve or place all of the weights on the regulator tip.

When the pressure cooker reaches pressure it begins to vent steam, rattle the weight... Note the Time, and Reduce the Heat until pressure is maintained, but you are not boiling off excess water. A weight that rattles once ever 15 - 30 seconds or so is perfectly set.

Min time in a pressure cooker is really 20 minutes. I sterilize all kinds of dirty stuff: Compost, Casing, whole grain substrates, Straw, Dung, Rags Even... I generally maintain pressure for 45 minutes, But, BRF in 1/2 pint jars are sterile after 20 min under 15 lbs of steam.

When the time is up, turn off the heat and let the thing cool without messing with it. I wait to open the lid until I am ready to work with the contents, frequently the following day.

Pressure Cooker Safety : Shroom Glossary : Sanitizing


By Cabal (Cabal) on Saturday, August 04, 2001 - 09:54 pm:

I just bought a Presto pressure cooker. Has anybody ever used one. I need some help on how to use it to sterilize my jars.

By Trollhunter (Trollhunter) on Saturday, August 04, 2001 - 10:10 pm:

does it have a gauge on the top or just the weight,not that it makes that much of a diffrence just put some water in it to just the bottom of the jars wait till the water starts to boil then put lid on.waiting till the water boils will push up the locking pin.or just wait till it pushes it self up,(with the latter being faster)if you only have the one with the weight on it leave jars in for 45 to 60 min.other than that what is it that you wanted to know .later

By Lzmaryann (Lzmaryann) on Saturday, August 04, 2001 - 11:02 pm:

I think All American has a good quality pressure cooker. It looks something like an autoclave sitting on end. No rubber gaskets, safety valve, high quality aluminum and pressure guage. Sweet!!!

By Cabal (Cabal) on Sunday, August 05, 2001 - 12:53 am:

Thanks for the info TH
I just wanted to know how long to keep it in the PC at 15psi. I have the kind with a weight on the top. what did you mean about letting the water boil before putting the lid on. I was just going to put the jars in it, turn it on high heat (electric range) and when the weight starts to rock (means it reached 15psi) start the timer for 45-60min. Does that sound right?
btw can I stack the jars (using the 1/2pint wide mouth)I only have a 6quart PC.

By Trollhunter (Trollhunter) on Sunday, August 05, 2001 - 01:28 am:

if you wait for the water to push up the locking pin it will take longer.once you put the lid on (once it is boiling)as soon as u turn the lid 99% of the time the pin will come up and then the preasure can start to rise.if they will fit in stacked do it .i let mine stay in for 45 to 60 mins .later :-)

By Poopypants (Poopypants) on Sunday, August 05, 2001 - 02:14 am:

I have one, What you want is the pressure cap rocking just gently for your 15PSI. I throw mine on the stove crank it to max wait till it starts rocking then back it off to 4.5 on the dial. Your stove will be different just take note where your burner dial is for a nice gentle rock. Let evrything cool naturally... especially if your using inverted lids, if you pour cold water on it... it and the jars will suck in air. You might as well spit in them.

Good luck,


By Poopypants (Poopypants) on Sunday, August 05, 2001 - 02:18 am:

Sorry forgot to add : everything I sterilize - 30 Mins.

compost/poop - 45 Mins.

Never had a prob with those times.

60 is overkill.

By Trollhunter (Trollhunter) on Sunday, August 05, 2001 - 03:41 am:

so do i ,but each to his own i guess ey lol.some times you just got to say screw it. and be better safe than sorry.

By Karna (Karna) on Sunday, August 05, 2001 - 08:15 pm:

With all pressure cookers, it is best to follow the manufacturers directions. It helps to make the thing (usually quite expensive) last a long time. As it is, if you use it a lot, you will have to get replacement sealant rings and overpressure plugs every so often.
With Prestos which are great pressure cookers/canners, the recommended method is to fill with however many quarts depending on the size of your model. Usually about 2-3 quarts of water but no higher than halfway or so up the sides of your jars, go on high heat till steam is visible, let the steam continue to escape for about 10 minutes, so the pressure inside starts to build. Often the pressure vent will rise to shut, when this happens, the weight can be placed on and pressure allowed to build to 15psi. At this point, the heat can be reduced a little so the weight is just gently rocking. At this time, start the timer. When done, turn off the stove. Allow the whole thing to cool to room temperature before opening.

By Cabal (Cabal) on Monday, August 06, 2001 - 02:54 pm:

Is it ok to cover the holes in the jars with masking tape and then tin foil before I put them in the PC. I read to loosen the lids a bit as well. Does that sound right?

By Karna (Karna) on Monday, August 06, 2001 - 03:21 pm:

that's fine

By Nanook of the North (Nanook) on Monday, August 06, 2001 - 08:25 pm:

Yeah, and you can stack jars. Cram em full.


By The Roc (Rochester) on Monday, August 06, 2001 - 10:00 pm:

Cabal right you are... once they hit the pc they will become sterile, up to then it just pays to be clean and tidy but the pc will kill it all if the pressure and time requirements are meet.


By Erinne (Erinne) on Tuesday, August 07, 2001 - 03:51 am:

can you also stack jars if you're using a large pot, or is it best to have just one layer?

By Cabal (Cabal) on Tuesday, August 07, 2001 - 04:21 am:

People say it's ok to stack them. I am going to stack mine.

By Mushy (Mushy) on Tuesday, August 07, 2001 - 12:37 pm:

I stack jars in a large pot and don't have any troubles.

By Cabal (Cabal) on Tuesday, August 07, 2001 - 02:44 pm:

I Pressure cooked my jars last night and on 3 of them I kept the lids a tad bit loose. (they had masking tape over holes and were covered with foil) Well, water got into them and in a few areas it looks wet. Do I need to dump these and start over? I loosened the lids alittle bit to see if it drys. I wasn't sure if I had to trash them and redo 'em. I did 10 jars and the ones that were on tight were fine. Although there does seem to be a tiny tiny bit of moisture on the bottom of the jars? Is this normal?

By Sporemagic (Sporemagic) on Wednesday, August 08, 2001 - 01:04 am:

you don't have to toss them although it may take a little longer to colonize. the moisture droplets you see is okay it's only condensation

By Cabal (Cabal) on Wednesday, August 08, 2001 - 05:27 pm:

I have very obvious wet patches in the jars that were just pressured cooked. You are saying that they will still colonize over the wet patches? I think my lids are bad on those jars, i dont know why so much water got into the jars on these. I also have little rust spots on the top of my jars around the holes. Is this a possible contam problem, when I stick the needles in them. I punched them with a nail. I keep the rubber edge face up when I close my lids. (jagged edge up) Any thoughts?

By Saney (Saney) on Wednesday, August 08, 2001 - 09:53 pm:

Cabal -

I steam steralized my jars, massive amounts of water got in (the substrate looked like mud).

I decided to try it out anyway... Jars completely colonized in 10 days, still fruiting as we speak.. mushrooms are nice and fat too. If anything, I think it helps to have a little extra water, or even alot.. as long as it's not overboard.

By Mushy (Mushy) on Thursday, August 09, 2001 - 01:16 pm:

I haven't had trouble with water in excess of the recommended.

the Rust is ok. I have seen someone post that they touch up the hole with fingernail polish to prevent the rust. I don't think it will cause you any problems, but if it gets too bad, it could get tough to tell if its just rust or a contam.

Pressure Cooker Safety

By Mr. Tambourine Man (Tambourine_Man) on Thursday, November 15, 2001 - 12:04 am:

Is it a good or bad idea to put jars in the fridge to cool faster to the innoculation point after pressure cooking them? I mean for both honey jars and substrate jars. Thanks!

By drylander (Romelur) on Thursday, November 15, 2001 - 12:29 am:

*shrug* I wouldn't, those things tend to be dirty, plus, they ussualy dehumidify, thus, drying your stuff out, then again, to each their own, have fun

By Cbee (Cbee) on Thursday, November 15, 2001 - 12:59 am:

i have used the fridge to cool down... seems to work fine for me... but if you have the patience then its best to let me sit overnight... might as well.. dont rush, thats the number one thing to remember in this hobby, even tho it is oh so very hard!!

By jim brown (Shrhobbyist) on Thursday, November 15, 2001 - 01:34 am:

I have also put them into the fridge to cool faster with no problem but the temperature change could cause contams to be sucked in. Usually I wait overnight to let them cool but if I am in a hurry and have to put them in the fridge I put the jars in a big ziplock bag or a air tight tupperware to help them. If you have to use the fridge make sure it is clean.

By Nan (Nanook) on Thursday, November 15, 2001 - 02:43 am:

Letting them cool slowly in the pressure cooker overnight is the best bet. Open the pc in a Clean Bathroom and Shoot the Jars. Then place Jars in a Clean Incubator.

The less you handle them, fiddle with them, peel the foil, cool them, heat them, move them, shed hair & skin on them, restack them, shuffle them, breath on them, shine light on them, breath on them some more... Look at them... IF YOU OPEN THEM YOU ARE CURSED!!!

The better they will be. It's simple

Patience is key here If you need something to occupy your time; prepare some more jars, plan a New Tek (to run alongside your working tek), upgrade your Incubator, your Fruiting Chamber... Clean Something....

Pressure Cooker Safety

By An guy (Boomer) on Thursday, November 15, 2001 - 05:12 am:

Mother Nan....'clean something, you kids these days...'

::boomer, laughing::

By Mr. Tambourine Man (Tambourine_Man) on Friday, November 30, 2001 - 06:55 pm:

I know the PF tek says to sterilize for 20 minutes, but I recall reading Nan say that he used 30 minutes. Is 20 still standard? I just want to settle on a time that kills and doesn't dry out. Thanks!

By Kaijan (Kaijan) on Friday, November 30, 2001 - 07:01 pm:

start timing when the gauge reads 15 PSI. I cooked for 30 mins. 20 is acceptable, 15mins is bare minimum. Obviously the longer you cook, the less chance of a contam will be missed....


Posted by: Lurker Feb 21 03, 01:02 PM GMT
Hey mycofriends,
My pressure cooker only goes up to 12 PSI. Is this good enough for grain teks? Some places say 12, others say 15. What if I keep it at 12 PSI for a longer time than usual, would that make up for the 3 PSI less? Thanks.

Posted by: Malformed Feb 21 03, 01:04 PM GMT
i dont think 3 psi is going to make much difference.

Posted by: BUNGHOLEO Feb 21 03, 04:51 PM GMT
Just increase your time on the heat biggrin.gif