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Offlinemickywilliams2
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Registered: 05/27/03
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killing ALL endospores possible????
    #2127808 - 11/21/03 04:03 PM (20 years, 4 months ago)

How hot and for how long would you have to cook grain in a PC to kill ALL endospores?
How hot does a PC get at 15 psi?
When the heat is raised and more steam is escaping from the PC, are the grains actually getting hotter or does the heat stay the same at 15 psi reguardless of how much heat you apply from outside?

A mycobag site says that the bags will hold up to 265 degrees. They also say you can keep a substrate bag for 4 months. Does this mean that the bag is free of all the endospores or would it actually take the endospores 4 months to take hold?


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OfflineChopperDave
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Re: killing ALL endospores possible???? [Re: mickywilliams2]
    #2127853 - 11/21/03 04:32 PM (20 years, 4 months ago)

I think you would cook/burn whatever was in the jars before you killed every last endospore

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OfflineAnnoA
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Re: killing ALL endospores possible???? [Re: mickywilliams2]
    #2127913 - 11/21/03 05:02 PM (20 years, 4 months ago)

>killing ALL endospores possible????
Yes.
Fractional sterilization.

>How hot does a PC get at 15 psi?
Read http://www.shroomery.org/index/par/23370


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OfflinefIsh in my head
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Re: killing ALL endospores possible???? [Re: Anno]
    #2130352 - 11/23/03 10:58 AM (20 years, 4 months ago)


Quick question about sterilizing with a pressure cooker.


What makes it so effective? Only the heat or the hot steam? If I pressure cook some grain jars filtered with polyfill, the hot steam will most likely penetrate the jar and sterilize.

What if I sterilize with only heat, no steam? Let say I seal a jar full of grain (no filter, just a sealing lid) and put this in the oven at 250F (like 15 psi) for 70 minutes. Will my grain be as sterile as if it was put in the PC?

.fs.

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Offlinemickywilliams2
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Re: killing ALL endospores possible???? [Re: fIsh in my head]
    #2130368 - 11/23/03 11:16 AM (20 years, 4 months ago)

they may explode with sealed lid.
If you loosen the lid they will prolly dry.

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OfflinefIsh in my head
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Re: killing ALL endospores possible???? [Re: mickywilliams2]
    #2130411 - 11/23/03 11:45 AM (20 years, 4 months ago)


yeah, I know it's not the way to go, i was just asking if the steam has something to do in the process of sterilization or if it's all thanks to Mr. Heat.

.fs.

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OfflineAnnoA
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Re: killing ALL endospores possible???? [Re: fIsh in my head]
    #2130462 - 11/23/03 12:16 PM (20 years, 4 months ago)

It?s the heat.
The steam is just a very good energy carrier, when it condenses on cooler surfaces.

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Invisiblemycofile
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Re: killing ALL endospores possible???? [Re: Anno]
    #2135388 - 11/25/03 03:54 PM (20 years, 4 months ago)

And don't forget the pressure. The pressure in a pc helps to get that heat into all the little nooks and crannies. Something may read as being a certain temperature, but that heat may not be thoroughly distributed throughout the substance. Not only throughout the mass of substance, but in all the little bumps and crannies on the surface of each piece of grain etc.

So I say it's the heat that kills, the steam that carries the heat, and the pressure and helps distribute it evenly.


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"From a certain point of view"
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I just looked at my profile and realized I had a website at one point in time on geocities, it's not there anymore and I have no idea what I had on it. Anybody remember my website from several years aga? PM if so please.

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OfflineParanoidSchizoid
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Re: killing ALL endospores possible???? [Re: mycofile]
    #2136381 - 11/25/03 10:34 PM (20 years, 4 months ago)

The pressure in a pressure cooker allows the water to reach higher temperatures without boiling off. Near sea level, water can reach a boiling point of 240 F at 15 psi. The boiling point will increase 1.8 F per psi. It's much like a modern auto cooling system. Most are sealed and designed to hold 15 psi. This allows your engine to run hotter than 212 F. So to answer your question, without the pressure, the temperature will not be high enough to kill endospores in grains. One way to ensure that most of the endospores are destroyed is to presoak the grains prior to pressure cooking, which many do already. Good luck to you


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OfflineHarveyWalbanger
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Re: killing ALL endospores possible???? [Re: fIsh in my head]
    #2138153 - 11/26/03 02:28 PM (20 years, 4 months ago)

They also tend to suck in an assload of contaminants when punching innoculation holes.... I'd definatly put the holes in before sterilizing.

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Invisibleshroomophile
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Re: killing ALL endospores possible???? [Re: ParanoidSchizoid]
    #2145035 - 11/29/03 05:43 PM (20 years, 4 months ago)

Quote:

The boiling point will increase 1.8 F per psi.



Not so.
1 psi= 212 F
3 psi= 220 F
5 psi= 228 F
10 psi=240 F
15 psi=250 F
20 psi=259 F
25 psi=267 F
page 21 "the mushroom cultivator" by stamets.
As the psi increases the temperature rises much more slowly.


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OfflineParanoidSchizoid
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Registered: 04/30/02
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Re: killing ALL endospores possible???? [Re: shroomophile]
    #2145165 - 11/29/03 06:48 PM (20 years, 4 months ago)

Thanks for the correction. I got that information from some page I can't even remember. It had nothing to do with cultivation. I have Paul's book. Stupid me for not looking in it.


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OfflineAnnoA
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Re: killing ALL endospores possible???? [Re: ParanoidSchizoid]
    #2145667 - 11/30/03 12:53 AM (20 years, 4 months ago)

This is the vapor pressure of water according to the ASME 1967 steam tables from 0 to 300 ?F.


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Offlineenimatpyrt
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Registered: 11/05/03
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Re: killing ALL endospores possible???? [Re: Anno]
    #2147083 - 11/30/03 03:31 PM (20 years, 4 months ago)

I'm not sure if pressure cooking does, in fact, kill every single spore. I think that it might kill the majority of them, but I know from working with autoclaves that instruments are QUITE hard to sterilize, and they are metallic and designed for sterilization. Maybe try PC'ing a jar, putting it in a sterile container for a bit and see if anything grows out.


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Invisiblemycofile
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Re: killing ALL endospores possible???? [Re: enimatpyrt]
    #2150012 - 12/01/03 04:55 PM (20 years, 3 months ago)

You can in fact achieve true sterilization in a pressure cooker. Jars can be left for years after PCing and remain contam free. Believe me, I gimaced when I found a jar, and thought "oh my god I quit growing years ago thats going to be one nasty f#$# jar!"
It was so clean I would have eaten it.


--------------------
"From a certain point of view"
-Jedi Master Obi Wan Kenobi

PM me with any cultivation questions.

I just looked at my profile and realized I had a website at one point in time on geocities, it's not there anymore and I have no idea what I had on it. Anybody remember my website from several years aga? PM if so please.

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