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dyskon
Bottom Dweller


Registered: 04/26/10
Posts: 122
Last seen: 13 years, 6 months
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PC/Autoclaving to destroy endospores, input RR?
#12566034 - 05/15/10 05:07 AM (13 years, 9 months ago) |
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All of the literature I have found so far states that all microbial life, including and specifically endospores, is killed when exposed to steam at 121c under 2 ATM of pressure for 15 minutes. (251f and 15 psi, exactly what your AA/prest runs at). Even without Tyndallization (pre-soaking to cause germination). Hell hospitals and professional piercers only autoclave at 15 PSI for 15 minutes.
Why are we PCing/Autoclaving for 90 minutes? It seems that at this point the only thing it is accomplishing is breaking down the sugars that the mycelium is using for foodage and causing an unnecessarily starchy mess.
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Numinosum
President of Turd Town


Registered: 05/19/09
Posts: 1,175
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Re: PC/Autoclaving to destroy endospores, input RR? [Re: dyskon]
#12566043 - 05/15/10 05:15 AM (13 years, 9 months ago) |
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Quote:
dyskon said: All of the literature I have found so far states that all microbial life, including and specifically endospores, is killed when exposed to steam at 121c under 2 ATM of pressure for 15 minutes. (251f and 15 psi, exactly what your AA/prest runs at). Even without Tyndallization (pre-soaking to cause germination). Hell hospitals and professional piercers only autoclave at 15 PSI for 15 minutes.
Why are we PCing/Autoclaving for 90 minutes? It seems that at this point the only thing it is accomplishing is breaking down the sugars that the mycelium is using for foodage and causing an unnecessarily starchy mess.
2 atmospheres of pressure is nearly 30 PSI not 15
-------------------- ...within my memory is the knowledge of hyper-light drive ships and how to build them. Doc_T's Efficiency Challenge
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dyskon
Bottom Dweller


Registered: 04/26/10
Posts: 122
Last seen: 13 years, 6 months
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Re: PC/Autoclaving to destroy endospores, input RR? [Re: Numinosum]
#12566047 - 05/15/10 05:18 AM (13 years, 9 months ago) |
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Our atomosphere + 1 atmosphere. We're sitting at one atmosphere by being on the ground.
http://wiki.answers.com/Q/What_is_air_pressure_at_sea_level_in_all_the_different_units_of_pressure
Edit: Citation
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Edited by dyskon (05/15/10 05:19 AM)
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Numinosum
President of Turd Town


Registered: 05/19/09
Posts: 1,175
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Re: PC/Autoclaving to destroy endospores, input RR? [Re: dyskon]
#12566051 - 05/15/10 05:21 AM (13 years, 9 months ago) |
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so true...
never thought of the inside of a pressure cooker to be relative
-------------------- ...within my memory is the knowledge of hyper-light drive ships and how to build them. Doc_T's Efficiency Challenge
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Numinosum
President of Turd Town


Registered: 05/19/09
Posts: 1,175
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Re: PC/Autoclaving to destroy endospores, input RR? [Re: Numinosum]
#12566055 - 05/15/10 05:26 AM (13 years, 9 months ago) |
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I'm not sure I understand why we call it 15psi if it is being cooked at 30psi
And what about if you are in the mountains.. if the gauge is relative then you could have problems.
-------------------- ...within my memory is the knowledge of hyper-light drive ships and how to build them. Doc_T's Efficiency Challenge
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dyskon
Bottom Dweller


Registered: 04/26/10
Posts: 122
Last seen: 13 years, 6 months
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Re: PC/Autoclaving to destroy endospores, input RR? [Re: Numinosum]
#12566066 - 05/15/10 05:32 AM (13 years, 9 months ago) |
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Quote:
Numinosum said: I'm not sure I understand why we call it 15psi if it is being cooked at 30psi
And what about if you are in the mountains.. if the gauge is relative then you could have problems.
On a macroscopic level the inside of the pressure cooker is effectively 15 psi. 30 PSI pushing out and 15 pushing in, including on the gauge.
When dealing with microbial life it doesn't work that way. They aren't like us. Large organisms are balanced inside and outside pressure wise. That's why your ears pop when you go above a certain altitude and you can get the benz if you surface too quickly while diving. Due to the lack of surface area on a microbe you use total pressure, not relative pressure. If you took a human or the pressure cooker at 15 psi and lauched them a 30,000 feet up they would explode. The same would not happen with an endospore.
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Doc_T
Random Dude




Registered: 03/06/09
Posts: 42,395
Loc: Colorado
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Re: PC/Autoclaving to destroy endospores, input RR? [Re: dyskon]
#12566265 - 05/15/10 07:31 AM (13 years, 9 months ago) |
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Quote:
dyskon said: Why are we PCing/Autoclaving for 90 minutes?
120+ in my case. Answer to question: because that is what works.
-------------------- You make it all possible. Doesn't it feel good?
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myco.alchemist
been there ~ done that

Registered: 03/27/10
Posts: 705
Loc:
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Re: PC/Autoclaving to destroy endospores, input RR? [Re: dyskon]
#12566303 - 05/15/10 07:48 AM (13 years, 9 months ago) |
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Quote:
dyskon said: All of the literature I have found so far states that all microbial life, including and specifically endospores, is killed when exposed to steam at 121c under 2 ATM of pressure for 15 minutes. (251f and 15 psi, exactly what your AA/prest runs at). Even without Tyndallization (pre-soaking to cause germination). Hell hospitals and professional piercers only autoclave at 15 PSI for 15 minutes.
Why are we PCing/Autoclaving for 90 minutes? It seems that at this point the only thing it is accomplishing is breaking down the sugars that the mycelium is using for foodage and causing an unnecessarily starchy mess.
It takes longer to cook a 25 lb turkey, than a 2.5 lb chicken. Same goes for sterilization with heat & moisture. You can PC a 500 ml liquid culture 20 minutes, to sterilize it @ 15psi/250F.
Now fill the same PC with quart jars or autoclave bags full of grain. The differance is the mass involved. Same as the 25 lb turkey verses the 2.5 lb chicken.
Ponder an oven. Heating it to 350F, doesn't cook a turkey in 5 minutes. The turkey has to stay @ that 350F for at least 2 hours, until it reaches an internal temp of 160F.
Make sense?
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