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KillaFromManilla
Stranger


Registered: 06/15/16
Posts: 7
Last seen: 7 years, 5 days
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I have had jars crack as I was putting them in the pressure cooker. I believe they were slightly damaged however, and the temperature change blew them out. Any large temperature swing between the water and glass can cause shock to the glass, that's why we don't throw warm water on our car windows to clean them off. However it's got to be a large swing of temperature for intact glass to give out. Basically, if you don't let it vent the air out it may read 15psi on a gauge or it may even rock your 15lb weight, but the psi inside the pressure cooker will not be that high. Your temperature won't be as high as you were intending. You may still have success at sterilization, you may not.
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,889
Loc: Milky way
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It will be that high in the PC if the gauge says it is or the rocker moves, 15 is 15 is 15. the partial pressure of steam will be less than 15 as some of that 15psi is made up of the dry air's pressure.
Pretend you have a balloon of 20% N2 and 80% O2 at 10psi The o2 contribute 8 psi the n2 contribution is 2psi. This is an oversimplified version and assumed ideal gas laws in effect.
Look up the gas law, ideal gas law, and partial pressure
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KillaFromManilla
Stranger


Registered: 06/15/16
Posts: 7
Last seen: 7 years, 5 days
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You're right about the pressure, I was mixed up obviously. I apologize, been a few years since college. However, the temperature portion is correct. Here's a very interesting experiment on several bacteria that shows the time increase needed to reach sterilization is greatly increased if air isn't evacuated. Just 25% air volume can double sterilization time of wet cotton swabs inoculated with two species of clostridium. It's really an interesting read.
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Loveshroomz777


Registered: 11/19/16
Posts: 616
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Any suggestions as to how high I should have my jars off the bottom of the PC I was thinking 1 inch and a half from what I have read what do you guys think
-------------------- PEACE, LOVE AND PSYCHEDELICS
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Pipefitter537
You're Not Yelping



Registered: 11/25/16
Posts: 715
Loc: SodoSopa
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That should be fine. How long of a cycle are you running?
-------------------- "You should never underestimate the predictability of stupidity"-Bullet Tooth Tony
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Loveshroomz777


Registered: 11/19/16
Posts: 616
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Ninety minutes and thanks for the help
-------------------- PEACE, LOVE AND PSYCHEDELICS
Edited by Loveshroomz777 (01/28/17 08:10 PM)
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,889
Loc: Milky way
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Quote:
Loveshroomz777 said: Any suggestions as to how high I should have my jars off the bottom of the PC I was thinking 1 inch and a half from what I have read what do you guys think
Use the trivet it comes with
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Loveshroomz777


Registered: 11/19/16
Posts: 616
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Ok thanks bodhisatta for the help!
-------------------- PEACE, LOVE AND PSYCHEDELICS
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Loveshroomz777


Registered: 11/19/16
Posts: 616
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So my PC comes with two trivets I am going to use one for the bottom and the second one to stack my second row of jars on top of my question is my trivet only sits about an inch above the pot will this be ok Can I fill the water a half inch up past trivet so that I have a inch and a half of water? Also this would mean that the jars will be in a half inch of water should this be fine thanks guys
-------------------- PEACE, LOVE AND PSYCHEDELICS
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,889
Loc: Milky way
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Yes the trivet is only a half inch tall. I use 3-4 quarts of water it goes half way up the side of the first layer of jars
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Loveshroomz777


Registered: 11/19/16
Posts: 616
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Re: Mirro pressure cooker [Re: bodhisatta] 1
#24049823 - 01/29/17 06:30 PM (7 years, 1 day ago) |
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Ok bodhisatta I will do it like you said thanks
I am so excited I just got the pressure cooker today I will be starting my grow on the 1st of February I will post pictures
-------------------- PEACE, LOVE AND PSYCHEDELICS
Edited by Loveshroomz777 (01/29/17 06:45 PM)
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Orbit
Stranger


Registered: 12/06/16
Posts: 127
Loc: Greatwhitenorth
Last seen: 5 years, 9 months
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A pc is not really that complicated. Hears some simple stuff that may shed some light for some.
Steam transfers heat better than air so you vent the air, venting times very depending on what you have in the PC. The PC vents the entire time so im not too concerned with venting. I see good steam i put the rocker on. You could do the same thing with air inside but it would take longer.
At seal level water boils at 100c. By raising the pressure 15psi you are raising the boiling point of water 15psi 121c. Killing temp. So you are basically raising the internal temp of the PC without boilng the water out of your media. The steam comes from the water you add. If you run your PC dry guess where the steam comes from. Media, not good, plus you are overheating the bottom of your PC.
All the rocker does is relieves exess pressure. So if the rocker is slowly rocking (good) you have 15 psi. If it is rocking crazy you have 15psi slightly more, but are wasting energy on creating more steam. If you really overheat, the safety will blow out preventing an explosion. If the rocker has stopped you are below 15psi 121c. Hope this sheds a little light.
-------------------- For Canadian trades PM me.
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LogicaL Chaos
Ascension Energy & Alien UFOs




Registered: 05/12/07
Posts: 69,363
Loc: The Inexpressible...
Last seen: 8 minutes, 51 seconds
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Re: Mirro pressure cooker [Re: Orbit]
#24050653 - 01/30/17 12:43 AM (7 years, 21 hours ago) |
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Well said
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Haywire
Wetspot Wizard



Registered: 12/29/13
Posts: 1,611
Last seen: 5 days, 21 hours
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dammit, bodhi, you should get your trusted tag just for this thread alone! talking about composure!
-------------------- Ciao mamma, guarda come mi diverto My grows Outdoor patches
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Loveshroomz777


Registered: 11/19/16
Posts: 616
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Re: Mirro pressure cooker [Re: Haywire]
#24054535 - 01/31/17 01:19 PM (6 years, 11 months ago) |
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So I vented my PC and now I have the heat on medium and the weight is rocking gently but ever so often it lets out a bunch of steam and the weight rocks a lot for like three seconds then it goes back to a slow gentle rock is my temperature too high
-------------------- PEACE, LOVE AND PSYCHEDELICS
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Loveshroomz777


Registered: 11/19/16
Posts: 616
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Nvm guys I lowered my heat and it fixed the problem
-------------------- PEACE, LOVE AND PSYCHEDELICS
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Orbit
Stranger


Registered: 12/06/16
Posts: 127
Loc: Greatwhitenorth
Last seen: 5 years, 9 months
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The pressure physically can't change too quick, maybe its just some water causing it. Some electric elements turn on and off and can cause a slight swing in pressure. Sounds like you found a happy medium.
-------------------- For Canadian trades PM me.
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The_breadsticks
Stranger


Registered: 09/23/16
Posts: 220
Last seen: 3 years, 5 days
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Quote:
Loveshroomz777 said: So I vented my PC and now I have the heat on medium and the weight is rocking gently but ever so often it lets out a bunch of steam and the weight rocks a lot for like three seconds then it goes back to a slow gentle rock is my temperature too high
it's supposed to do that, set your heat to make it happen every 2 mins or so. If not, you're under pressure.
-------------------- FREE TUMP
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Loveshroomz777


Registered: 11/19/16
Posts: 616
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After I adjusted my heat the weight was just rocking back and forth gently without it going out of control for a couple seconds every two minutes do you guys think my jars still got sterelized
-------------------- PEACE, LOVE AND PSYCHEDELICS
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,889
Loc: Milky way
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15psi is 15psi
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