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murder_of_crows
Stranger
Registered: 08/03/04
Posts: 8
Last seen: 18 years, 6 months
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Altitude
#3079664 - 09/01/04 08:13 PM (19 years, 6 months ago) |
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I can't seem to find anything on adjusted pressure cooker time with respect to altitude. Is there any rule of thumb??? I am at approximately 5300 feet. Should I let it cook at 15 psi for 90 minutes instead of an hour? I searched the forums and I can't find anything. Any help or direction would be greatly appreciated.
Murd
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Fucknuckle
Dog Lover
Registered: 04/24/04
Posts: 6,762
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Good question And welcome to the shroomery I am going to put some time searching for you let me see what I can find.
-------------------- What it is, is what it is my Brother. It is as it is, so suffer thru it.
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murder_of_crows
Stranger
Registered: 08/03/04
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Last seen: 18 years, 6 months
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Cool, I would appreciate that!
Murd
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danelectro
Disenfranchised
Registered: 07/01/02
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Loc: Left of Oblivion
Last seen: 18 years, 7 months
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I'd imagine it would be very similar to the amount of time you add for plain boiling water, been alot time since I've been up that high so I don't remember, but I'm sure you could find that offsite (or on some of the food in your kitchen) and use that as a general guide.
-------------------- We should really love each other, in peace and harmony. Instead we're fussing and fighting, like we ain't supposed to be.-Bob Marley The people, the still sleeping mass which it was necessary to mobilize and its vanguard, the guerrillas. -Che
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YahoKa
Just a guy.
Registered: 06/21/04
Posts: 124
Loc: Canadian
Last seen: 18 years, 3 months
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Wait ... but the pressure outside doesn't change the pressure of the pressure cooker... so the water inside will boil at the same temp anywhere, right?
-------------------- Hang on tightly ... and let go lightly.
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fastfred
Old Hand
Registered: 05/17/04
Posts: 6,899
Loc: Dark side of the moon
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Re: Altitude [Re: YahoKa]
#3081197 - 09/02/04 03:28 AM (19 years, 6 months ago) |
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No
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YahoKa
Just a guy.
Registered: 06/21/04
Posts: 124
Loc: Canadian
Last seen: 18 years, 3 months
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Re: Altitude [Re: fastfred]
#3082026 - 09/02/04 09:44 AM (19 years, 6 months ago) |
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Why not? 15 psi is 15 psi is 15 psi, whether the surrounding pressure is 0.5 atms or 1 atms.
-------------------- Hang on tightly ... and let go lightly.
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Mykey
spectraltraveler
Registered: 04/07/04
Posts: 542
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Boiling Point Of Water* Altitude in Feet Altitude in Meters Degrees F. Degrees C. 0 0 212.0 100.0 500 152 211.0 99.4 1000 305 210.0 98.9 2000 610 208.2 97.9 3000 914 206.2 96.8 4000 1219 204.4 95.8 5000 1524 202.6 94.8 6000 1829 200.7 93.7 7000 2134 198.7 92.6 8000 2438 196.9 91.6 10,000 3048 194.0 90.0 12,500 3810 189.8 87.7 14,000 4267 187.3 86.3 Basicaly for every thousand feet above two thousand feet above sea level you will need to add 5% to the cook time.
This rule of thumb applies to cooking when the instructions dont say" from the time of the wobble ". When shrooms are concerned the time for sterilization is always taken from the time you reach 15psi,which is 15psi whether you are in the death valley or on the highest mountain. So if you are looking to sterilize altitude doesnt matter because you are only concerned with the time at 15psi and not the time it takes for the internal pressure to reach that point.
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ATWAR
Connoisseur
Registered: 01/26/03
Posts: 1,640
Loc: #108768 in line...
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Re: Altitude [Re: Mykey]
#3083396 - 09/02/04 03:25 PM (19 years, 6 months ago) |
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Quote:
Mykey said: So if you are looking to sterilize altitude doesnt matter because you are only concerned with the time at 15psi and not the time it takes for the internal pressure to reach that point.
This is not true. From TMC by Paul Stamets:
Those cultivating at higher elevations must cook at higher pressures to achieve the same sterilization effect. Increase the amount of pressure over the recommended amount based on the difference of the boiling point at sea level and one's own altitude. For example, at 5000 feet the difference in the boiling point of water is approximately 10?F. This means the pressure must be increased to 20 psi, 5 psi above the recommended 15 psi sea level standard, to correspond to a 10?F increase in temperature. (actually temperature remains the same; it is pressure that differs).
-------------------- To give is to live...
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shirley knott
not my real name
Registered: 11/11/02
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Re: Altitude [Re: ATWAR]
#3083454 - 09/02/04 03:34 PM (19 years, 6 months ago) |
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nice find
-------------------- buh
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YahoKa
Just a guy.
Registered: 06/21/04
Posts: 124
Loc: Canadian
Last seen: 18 years, 3 months
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Re: Altitude [Re: ATWAR]
#3083500 - 09/02/04 03:41 PM (19 years, 6 months ago) |
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Ok, this is really bothering me now ... even if you are in fuking space, if the pressure cooker is at 15 PSI, the water in the pressure cooker will boil at the same temp as in a pressure cooker at sea level. The time to get to 15 PSI may change, but that's irrelevant to how long you cook at 15 psi. The boiling point of the water outside of the pressure cooker changes, but not inside since the pressure is constant! It is a closed container, i.e. a closed system. I don't know if statements never studied his chemistry or what, but I think he's wrong.
-------------------- Hang on tightly ... and let go lightly.
Edited by YahoKa (09/02/04 03:43 PM)
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Fucknuckle
Dog Lover
Registered: 04/24/04
Posts: 6,762
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Re: Altitude [Re: YahoKa]
#3083548 - 09/02/04 03:51 PM (19 years, 6 months ago) |
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I almost agree with you It is a hard thing to grasp. I don't think I understand it ???? What you are saying makes perfect sense. Mabey if using an completely in closed PC that allows no release of steam agrees with your point. And a pC that uses a rocker or weight and releases steam favors the other point. I don't think I am 2 sure of what to think here. Being a metal worker I have fabricated pressure vessels several times and I think I know somthing about the intereactions between different presures. So I do feel you dude. An enclosed pressure vessel holds the same pressure even if it is built inside another presure vessel. I know this is true. I have fabricated very large intercoolers. Which were two hugh pressure vessels. One inside the other at different pressures. So I dont know What to say????? I would hate to try an disagree with everybody and Paul Stamets.
-------------------- What it is, is what it is my Brother. It is as it is, so suffer thru it.
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Evolving
Resident Cynic
Registered: 10/01/02
Posts: 5,385
Loc: Apt #6, The Village
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Re: Altitude [Re: YahoKa]
#3083550 - 09/02/04 03:51 PM (19 years, 6 months ago) |
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Quote:
YahoKa said: ... even if you are in fuking space, if the pressure cooker is at 15 PSI, the water in the pressure cooker will boil at the same temp as in a pressure cooker at sea level.
No, 15 PSI as measured in a pressure cooker is in relation to the air pressure outside of the pressure cooker, it's actually a 15 PSI difference.
-------------------- To call humans 'rational beings' does injustice to the term, 'rational.' Humans are capable of rational thought, but it is not their essence. Humans are animals, beasts with complex brains. Humans, more often than not, utilize their cerebrum to rationalize what their primal instincts, their preconceived notions, and their emotional desires have presented as goals - humans are rationalizing beings.
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YahoKa
Just a guy.
Registered: 06/21/04
Posts: 124
Loc: Canadian
Last seen: 18 years, 3 months
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Re: Altitude [Re: Evolving]
#3083592 - 09/02/04 04:00 PM (19 years, 6 months ago) |
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Yay, finally an answer that fully makes sense. Case closed =)
-------------------- Hang on tightly ... and let go lightly.
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ATWAR
Connoisseur
Registered: 01/26/03
Posts: 1,640
Loc: #108768 in line...
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Re: Altitude [Re: Evolving]
#3083600 - 09/02/04 04:01 PM (19 years, 6 months ago) |
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Exactly. The pressure of the outside air must be taken into account. If the pressure of the outside air is less, then it will take less internal pressure to move the weight (and release steam)...
If you operated your PC in a vacuum, it would take considerably less heat to boil the water than at sea level pressures...
-------------------- To give is to live...
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scatmanrav
Brainy Smurf
Registered: 05/08/04
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Re: Altitude [Re: ATWAR]
#3083974 - 09/02/04 05:39 PM (19 years, 6 months ago) |
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But if you just use one with a guage and not a weigth or rocker you just do the normal 15 PSI right? Because won't it be reading the difference?
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Fucknuckle
Dog Lover
Registered: 04/24/04
Posts: 6,762
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Re: Altitude [Re: ATWAR]
#3084155 - 09/02/04 06:22 PM (19 years, 6 months ago) |
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After thinking about this for a while....??? I realized my mistake. DUH...
The pressure in the pc is only 15 psi higher then the original air pressure before you close the lid. No matter where your at on the planet.
-------------------- What it is, is what it is my Brother. It is as it is, so suffer thru it.
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ricelicker
The Dude'sImaginary Friend
Registered: 03/31/00
Posts: 722
Loc: The Yard
Last seen: 3 years, 2 months
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So my cousin in the Rocky Mountains doesn't have to make any adjustments to cooking time?
-------------------- "my brain waves travel at half the speed afta we..." -del tha funkee "Two men looked out through prison bars...one saw the mud, one saw the stars." -anonymous
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ATWAR
Connoisseur
Registered: 01/26/03
Posts: 1,640
Loc: #108768 in line...
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Quote:
scatmanrav said: But if you just use one with a guage and not a weigth or rocker you just do the normal 15 PSI right? Because won't it be reading the difference?
The guage is reading the difference. Pressure guages use the outside air as a reference.
Look at it this way: At sea level, the pressure of the air is 14.7 psi. This corresponds to 29.7 psi inside the pressure cooker. At 5000 feet, the air pressure is reduced to 12.2 psi. This means that the pressure inside the PC is reduced to 27.2 psi. This total pressure is not measured by the guage, only the difference is measured. Because the total pressure is reduced, the temperature required to boil the water (and therefore produce steam to increase pressure) is also reduced.
Am I the only person who paid attention in physics class?
-------------------- To give is to live...
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ricelicker
The Dude'sImaginary Friend
Registered: 03/31/00
Posts: 722
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Re: Altitude [Re: ATWAR]
#3084244 - 09/02/04 06:53 PM (19 years, 6 months ago) |
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So what does that translate to in terms of cooking time etc at higher alt? If you have a PC with 1 rocking weight, there's nothing you can do besides cooker longer right? Am I missing something?
-------------------- "my brain waves travel at half the speed afta we..." -del tha funkee "Two men looked out through prison bars...one saw the mud, one saw the stars." -anonymous
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