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biologys
Mycologist in Trainning




Registered: 12/21/09
Posts: 4,622
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question reguarding agar
#13990730 - 02/19/11 04:01 PM (12 years, 11 months ago) |
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ok so i've been playing a bit with agar, normally i PC at 15 PSI for 20-25 mins
but since i'm only doing a small amount, i want to use my smaller PC, which only goes to 10 PSI
how much longer should i PC to make up for 5 less PSI?
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ProfessorPinHead
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Re: question reguarding agar [Re: biologys]
#13990805 - 02/19/11 04:13 PM (12 years, 11 months ago) |
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Use a little one like that and just left it on for 30 min instead.
I went to get a separate PC for making cultures. I had gotten home and didn't realize it was a 10 psi cooker... Figgen walmart 
Anyway, I only used it twice before returning it but both times it was for agar. I didn't have any problems but I would recommend just grabbing a 15 PSI cooker if you can.
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biologys
Mycologist in Trainning




Registered: 12/21/09
Posts: 4,622
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i have 2 15 psi cookers, lol i just didnt' want to mess them up for one jar of agar...so im using my small 6 qrt one
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ProfessorPinHead
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Re: question reguarding agar [Re: biologys]
#13990832 - 02/19/11 04:21 PM (12 years, 11 months ago) |
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It should be fine. I was just sayin' I wouldn't make a habit out of it. I would definitely add ten minutes to the timeline though
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Bacchus
Lurker




Registered: 10/10/06
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30 minutes is good. Since you're decreasing the presure by 1/3, you need to increase the time by 1/3.
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Living on a no-Flash diet is way easier than you think. Give it a shot.
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ProfessorPinHead
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Re: question reguarding agar [Re: Bacchus]
#13992020 - 02/19/11 08:18 PM (12 years, 11 months ago) |
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Quote:
Bacchus said: 30 minutes is good. Since you're decreasing the presure by 1/3, you need to increase the time by 1/3.
Thats where I was tryin' to go with it.
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bateyes88
Professional Amateur



Registered: 09/15/10
Posts: 901
Loc: Anytown, USA 12345
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I know that in canning, there is no substitute for that 5 extra psi. There is a 9 degree temp difference and some bacteria live in that 9 degree zone- so even if you cooked at 10 psi all day long, you wouldnt kill ALL bacteria. At 15 psi, a pressure cooker can get to 121C (249.8F), at 10 psi it can only get to 116C (240.8F). Unfortunately, there are many organisms that can survive at 240F (Botulism is one of the ones that lives between 240*F and 249*F.)
I have no idea if that carries over into our mycology needs... If the above posters have had good luck w/ 10 psi I have no reason to doubt em! Just wanted you to know that 10 PSI isn't safe for canning.
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ProfessorPinHead
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Re: question reguarding agar [Re: bateyes88]
#13992399 - 02/19/11 09:20 PM (12 years, 11 months ago) |
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those organisms are called extremophiles and they are single celled bacteria. The oldest life form on this planet. FYI.
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bateyes88
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Do they mess w/ us r.e. mycology? Do we need to worry about em?
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ProfessorPinHead
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Re: question reguarding agar [Re: bateyes88]
#13996127 - 02/20/11 03:09 PM (12 years, 11 months ago) |
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Not if you sterilize your substrate properly.
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bateyes88
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But will 10 psi(240F) kill em? If not, then no amount of extra time will help. OP would need to trade in for 15 psi...
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