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Haha, pressure cookers aren't really a secret. They are found in most households in India. In the U.S., for years there was an irrational fear of pressure cooke
by wenc 8y ago
Haha, pressure cookers aren't really a secret. They are found in most households in India. In the U.S., for years there was an irrational fear of pressure cookers exploding so they never really caught on until the Instapot came along (which some people don't realize is a pressure cooker). The fact is, pressure cooker tech is very old and remarkably safe. It's been "beta-tested" by millions of people in India.
The science is simple: water vaporizes at 212F/100C at atmospheric pressure. But if you increase the pressure, the boiling point increases [1]. This means instead of cooking temperatures maxing out at 212F, the cooker lets one achieve higher temperatures. This is why pressure cookers are able to cook faster -- the temperatures are simply higher.
Meats cooked with pressure cookers tend to come out more tender (if you don't let them dry out) in a shorter amount of time.
[1] Water phase diagram. Notice that on the vaporization-condensation part of the curve, when P increases, the T crossover point also increases https://courses.lumenlearning.com/suny-chem-atoms-first/chapter/phase-diagrams-2/ https://courses.lumenlearning.com/suny-chem-atoms-first/chap...
- moonka 8y ago>In the U.S., for years there was an irrational fear of pressure cookers exploding so they never really caught on until the Instapot came along (which some people don't realize is a pressure cooker). The fact is, pressure cooker tech is very old and remarkably safe. It's been "beta-tested" by millions of people in India. I have a feeling that the recent popularity of the InstaPot will make pressure cookers much more popular in years to come.
- wenc 8y agoThe funny thing is the Instapot was invented by a bunch of laid-off Nortel engineers in Canada (the owner has a Ph.D. in CS). Those guys somehow managed to figure out how to sell boatloads of pressure cookers to Americans when so many before them have tried and failed.
- r00fus 8y agoI don't. The instapot still takes plenty of time for the actual eating to be ready as you have to wait for the pressure to release.
- avtar 8y agoWhy not twist the valve to release pressure quickly?
- mrob 8y ago1. It fills the room with steam. 2. It makes the food bubble up onto the lid so you have to clean it (the lid usually remains perfectly clean because only steam touches it). I only use quick release for delicate foods like steamed vegetables.
- wenc 8y agoWith electronic pressure cookers, there are usually two modes: quick release and natural release.[1] Natural release is slower but tends to produce better results for large cuts of meat. For most other food, quick release should work just fine. (the principle is the same for non-electronic pressure cookers; quick-release there simply means running cold water on the pot with the lid closed to depressurize) [1] https://www.pressurecookingtoday.com/quick-pressure-release-or-natural-pressure-release/ https://www.pressurecookingtoday.com/quick-pressure-release-...
- vikiomega9 8y agoErr beta-tested?
- wenc 8y agoI guess tested-in-production? They've had a long safety track record in other parts of the world, in particular India.
- twic 8y ago> The science is simple: water vaporizes at 212F/100C at atmospheric pressure. But if you increase the pressure, the boiling point increases [1]. This means instead of cooking temperatures maxing out at 212F, the cooker lets one achieve higher temperatures. This is why pressure cookers are able to cook faster -- the temperatures are simply higher. The science, it seems, is not quite as simple as you think: https://genuineideas.com/ArticlesIndex/pressurecooker.html https://genuineideas.com/ArticlesIndex/pressurecooker.html
- wenc 8y agoI don't think the article is accurate. It really isn't density that is directly responsible for the faster cooking (though the increased impingement is a contributing factor). The more direct cause is heat. Cooking is the result of heat transfer. When you raise the vaporization temperature (by raising the pressure), more heat is transferred in the process of getting to that temperature and vaporizing the steam. To verify this, we can do an enthalpy calculation. Specific enthalpy (h) for water at 25C, 1 atm is 104920 J/kg. At 1 atm, the enthalpy for gaseous steam at vaporization is 2.676e6 J/kg. For pressure cookers, at 2 atm, the enthalpy is 2.707e5 J/kg. That is an extra 31000 J/kg.