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Gratos
Just thinkin anddrinkin

Registered: 08/21/05
Posts: 1,374
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How exactly are we steralizing our jars when we put them in the cooker?
#14180433 - 03/25/11 04:50 AM (12 years, 10 months ago) |
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How is the steam in a pressure cooker steralizing our jars? Is it the steam or the heat or pressure? For some reason this question is stuck in my mind. Its not the steam or our moisture content would be screwed. Is it the pressure? If it was the heat a simple bake would work. Im confused, please enlighten me.
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virus1824
Mr Mushroom



Registered: 09/25/05
Posts: 1,751
Loc: Europe
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Re: How exactly are we steralizing our jars when we put them in the cooker? [Re: Gratos]
#14180477 - 03/25/11 05:17 AM (12 years, 10 months ago) |
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The pressure just raises the boiling point to 121C. The heated steam ensures overall temperature without fluctuations within the PC, the heat itself kills most of the contaminations.
-------------------- A weekend wasted is never a wasted weekend
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LeopardMan
Constantly changing



Registered: 09/21/09
Posts: 5,463
Loc: A tree house
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Re: How exactly are we steralizing our jars when we put them in the cooker? [Re: Gratos]
#14180876 - 03/25/11 08:22 AM (12 years, 10 months ago) |
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Heat
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You have to die a few times before you can really live. -Charles Bukowski-
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Gratos
Just thinkin anddrinkin

Registered: 08/21/05
Posts: 1,374
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Re: How exactly are we steralizing our jars when we put them in the cooker? [Re: LeopardMan]
#14180985 - 03/25/11 08:57 AM (12 years, 10 months ago) |
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I must be missing something (Ive been on something of a binge lately). If its just heat doing the job, why cant we just put our jars in the oven?
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LeopardMan
Constantly changing



Registered: 09/21/09
Posts: 5,463
Loc: A tree house
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Re: How exactly are we steralizing our jars when we put them in the cooker? [Re: Gratos]
#14181011 - 03/25/11 09:05 AM (12 years, 10 months ago) |
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Because if you put your jars in the oven they will dry out completely. The center of a grain jar in a PC, on the contrary, is heated by heat transfer (or heat conduction).
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You have to die a few times before you can really live. -Charles Bukowski-
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Doc_T
Random Dude




Registered: 03/06/09
Posts: 42,395
Loc: Colorado
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Re: How exactly are we steralizing our jars when we put them in the cooker? [Re: LeopardMan]
#14181019 - 03/25/11 09:08 AM (12 years, 10 months ago) |
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Also, in the oven your jars can't get above 100C. PC temps are much higher.
-------------------- You make it all possible. Doesn't it feel good?
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Nook
No0b
Registered: 03/28/10
Posts: 6
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Re: How exactly are we steralizing our jars when we put them in the cooker? [Re: LeopardMan]
#14181024 - 03/25/11 09:09 AM (12 years, 10 months ago) |
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I've never used a pressure cooker. Just a normal pot with a lid. Two hours vigorous boil of the two inches of water at the bottom. Topping it up occassionally. Never had even one contam issue. ...so i'd assume, in answer to your question, it is the heat, not pressure
Edited by Nook (03/25/11 09:14 AM)
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RogerRabbit
Bans for Pleasure



Registered: 03/26/03
Posts: 42,214
Loc: Seattle
Last seen: 11 months, 4 days
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Re: How exactly are we steralizing our jars when we put them in the cooker? [Re: Nook]
#14181068 - 03/25/11 09:22 AM (12 years, 10 months ago) |
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It's the heat. The steam helps to transfer the heat because of the moisture within. Also, since the steam is at 100% humidity, it prevents the substrate from drying out during sterilization. RR
-------------------- Download Let's Grow Mushrooms semper in excretia sumus solim profundum variat "I've never had a failed experiment. I've only discovered 10,000 methods which do not work." Thomas Edison
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Sillicybin
Registered: 02/14/05
Posts: 2,134
Loc:
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Re: How exactly are we steralizing our jars when we put them in the cooker? [Re: RogerRabbit]
#14181170 - 03/25/11 09:57 AM (12 years, 10 months ago) |
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Quote:
RogerRabbit said: The steam helps to transfer the heat because of the moisture within.
This. The water vapor in steam is very efficient at transferring heat, where air is not.
Quote:
Wikipedia said: It is very important to ensure that all of the trapped air is removed, as hot air is very poor at achieving sterility. Steam at 134 °C can achieve in 3 minutes the same sterility that hot air at 160 °C takes two hours to achieve.
http://en.wikipedia.org/wiki/Autoclave
When water changes from liquid to gas, it takes a lot of energy with it, which cools the remaining liquid. Under standard pressure, that is why you can never get liquid water above 100*C. Increasing the pressure allows us to get the water to around 121*C before it changes to gas, which in turn makes the steam more effective at sterilizing.
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bootster


Registered: 02/22/11
Posts: 1,531
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Re: How exactly are we steralizing our jars when we put them in the cooker? [Re: Sillicybin]
#14181373 - 03/25/11 10:47 AM (12 years, 10 months ago) |
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The steam actually takes that latent heat that is absorbed during the transition from liquid to gas state and has the ability to release it to the jars much more effectively than water alone. That is why steam can scald you so quickly,it simply contains more energy. Under pressure,the steam @ 15 lb in a PC is 250 degrees F,as is the water,but the steam contains the added latent heat of evaporation that gets transferred to the jars.
It is the most efficient heat transfer to steam the jars rather than have the jars sitting in a lot of water. The ideal situation is to elevate the jars above the water level to keep them in a steam bath rather than sitting in the water.
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