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FallenShroom
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Registered: 05/01/03
Posts: 879
Last seen: 16 years, 9 months
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Microwave and Pressure cooker heat
#1696547 - 07/08/03 02:05 PM (21 years, 6 months ago) |
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I have been seeing allot of post concerning microwave Vs pressurecookers so you do the comparison hope this helps out....
Here is the table of heat for microwaves 650-800 watt also pressure cooker heat
Pessure cooker heat at 15psi is 250 Degrees
Pressure
lbs per sq inch Temperature
5 lbs 228 ? F
10 lbs 240 ? F
15 lbs 250 ? F
30 lbs 270 ? F <----- auto clave
Microwave
100 - 90% power 425 - 500 degrees, deep fat fry, broil or stove-top
burner on "high"
80% 375 - 425 degrees
70% 350 - 375 degrees or medium-high on stove-top
60 - 50% 300 - 350 degrees or medium on stove-top
40 - 30% 225 - 300 degrees or medium-low on stove-top
20% 200 - 225 degrees
10% 150 - 200 degrees or lowest setting on stove-top
To understand how a pressure cooker works, you need to know just a little about physics. Simply put, water boils at 212 Farenheit. At this point, no matter how long you continue to boil, it always stays the same temperature. As the water evaporates and becomes steam it is also the same temperature, 212 F.
The only way to make the steam hotter (and/or to boil the water at a higher temperature) is to put the system under pressure. This is what a pressure cooker does. Steam has six times the heat potential when it condenses on a cool food product. This increased heat transfer potential is why steam is such an effective cooking medium.
If you put water into a pot and cover it with a tightly sealed lid, the steam will remain trapped and pressure will build and that rises the temperature at which the liquid will boil. So at 15psi your food is cooking at about 250 instead on just 212
Consider the difference in cooking power between an oven and steamer in this example. You can put your hand in a 400[degrees]F oven and not burn yourself but put your hand over a boiling tea kettle and the 212[degrees]F steam will scald immediately. This is due to the different methods of heat transfer: air is a poor conductor; water is a good conductor. Think of being outside when it's 70 degrees F (quite pleasant) versus being in a pool of water at 70 degrees (feels very cold).
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Anno
Experimenter



Registered: 06/17/99
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Re: Microwave and Pressure cooker heat [Re: FallenShroom]
#1696591 - 07/08/03 02:18 PM (21 years, 6 months ago) |
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This table for the microwave is incorrect and useless, you are saying yourself that water can?t get hotter than 212?F at atmospheric pressure.
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FallenShroom
Shagadelic

Registered: 05/01/03
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Last seen: 16 years, 9 months
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Re: Microwave and Pressure cooker heat [Re: Anno]
#1696596 - 07/08/03 02:22 PM (21 years, 6 months ago) |
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no water can not go above 212 without pressure that is my point
Hmmm so your stove you can set at 500 degrees just cause water wont get that hot does not mean your stove cant put out 500 degrees
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Edited by FallenShroom (07/08/03 02:23 PM)
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Anno
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Re: Microwave and Pressure cooker heat [Re: FallenShroom]
#1696598 - 07/08/03 02:22 PM (21 years, 6 months ago) |
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But what?s the meaning of the microwave table then? It implies that it can heat above 212?F, which is not true.
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FallenShroom
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Re: Microwave and Pressure cooker heat [Re: Anno]
#1696613 - 07/08/03 02:27 PM (21 years, 6 months ago) |
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yes it can reach 500 degrees at 100% power but your water will still not go above 212 place oil in there you will reach that temp. thats why i wrote that water cant go above 212 with out pressure
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Anno
Experimenter



Registered: 06/17/99
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Re: Microwave and Pressure cooker heat [Re: FallenShroom]
#1696623 - 07/08/03 02:30 PM (21 years, 6 months ago) |
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Still, useless. You don?t have oil in your mushroom substrate, at least not without water.
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FallenShroom
Shagadelic

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Posts: 879
Last seen: 16 years, 9 months
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Re: Microwave and Pressure cooker heat [Re: FallenShroom]
#1696625 - 07/08/03 02:31 PM (21 years, 6 months ago) |
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Anno please give me any advice on how to reword that. I feel that it is clear but maybe not any help you could give would be honored. I think people need to know the reasons why microwave sterilization does not work but pasteurizing in microwave may
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FallenShroom
Shagadelic

Registered: 05/01/03
Posts: 879
Last seen: 16 years, 9 months
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Re: Microwave and Pressure cooker heat [Re: FallenShroom]
#1696635 - 07/08/03 02:34 PM (21 years, 6 months ago) |
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you know whats useless you telling me that. i know water wont go to 500 degrees hmmm let me see i have a stove that says 500 degrees on it hmmmm i place this jub of water in there will it get to 500 degrees NO but sorry microwave can heat to 500 also just cause water wont get that hot does not mean that temperature DOES NOT EXIST ......
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Anno
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Re: Microwave and Pressure cooker heat [Re: FallenShroom]
#1696637 - 07/08/03 02:35 PM (21 years, 6 months ago) |
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>so your stove you can set at 500 degrees just cause water wont get >that hot does not mean your stove cant put out 500 degrees
The stove does PHYSICALLY get to 500?F, the microwave oven doesn?t. The table is implying something that is not the case.
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underground
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Registered: 06/23/03
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Re: Microwave and Pressure cooker heat [Re: Anno]
#1696640 - 07/08/03 02:35 PM (21 years, 6 months ago) |
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but if you are nuking in a sealed container, wont liquid water inside the container be converted to steam, which will build up and increase the pressure inside the container. increased pressure means higher steam temps... in my warped mind, this makes sense
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FallenShroom
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Re: Microwave and Pressure cooker heat [Re: FallenShroom]
#1696641 - 07/08/03 02:35 PM (21 years, 6 months ago) |
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SO for you to say my table on microwave heat is incorrect sorry but you are wrong this time
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FallenShroom
Shagadelic

Registered: 05/01/03
Posts: 879
Last seen: 16 years, 9 months
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Re: Microwave and Pressure cooker heat [Re: FallenShroom]
#1696646 - 07/08/03 02:37 PM (21 years, 6 months ago) |
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yes if you nuke in a sealed container i would say steam would build but can your plastic container with stand 15psi or would it just explode?
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Anno
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Re: Microwave and Pressure cooker heat [Re: FallenShroom]
#1696650 - 07/08/03 02:39 PM (21 years, 6 months ago) |
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>This is due to the different methods of heat transfer: air is a poor >conductor; water is a good conductor.
This is incorrect. This is because of the evaporation(condensation) heat, not because the water is a better heat conductor. You are saying it right just a paragraph further up, and then revert to the incorrect explanation...why that?
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underground
welcome to the underground

Registered: 06/23/03
Posts: 191
Loc: colorful colorado
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Re: Microwave and Pressure cooker heat [Re: FallenShroom]
#1696660 - 07/08/03 02:42 PM (21 years, 6 months ago) |
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i dont know. just speculating here... 15psi is about twice the normal atmospheric pressure. i bet a good sealing tupperware can hold in that kind of pressure.
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FallenShroom
Shagadelic

Registered: 05/01/03
Posts: 879
Last seen: 16 years, 9 months
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Re: Microwave and Pressure cooker heat [Re: Anno]
#1696676 - 07/08/03 02:46 PM (21 years, 6 months ago) |
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evaporation correct the point of this was to expain that water cant get to the heat a pc can cause of pressure like i keep saying put a kettle on say a flame measure the heat of the flame around 500 degrees so since that is 500 degrees still water will break at 212 with out pressure i do see what your saying i just cant figure out how to word it
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