RPCookin said: "The point of the pressure cooker is to create a higher pressure in the cooker. Just because the ambient pressure is less, does the pressure cooker pressurize less too?"
Yes. The pressure relief valve (the part that goes Hssssss...." relieves the pressure differential between the inside and outside of the pressure cooker. If it's set for 10 pounds (just an example), it will release the pressure 10 p.s.i. above the ambient pressure, no matter what the local pressure is.
In short, local altitude does matter.
What you say could be correct, if the pressure exerted by the outside ambient pressure determined the force placed on the pressure regulator. But at least in both of my pressure cookers, there are weights that regulate the pressure. It takes 11.5 lbs. psi to lift the weight of the regulator to allow steam to escape. My larger Pc has added weight rings that can be added so that the internal pressure of the pot requires 11.5, 12, or 15 lbs. of internal pressure to release steam, regardless of the ambient atmospheric pressure. The deciding factors are the rigid, closed pot, and the weighted pressure regulator. The inside conditions of the pressure cooker are isolated from outside conditions except for gravity. If you were on the moon, it would take much less pressure to cause the PC to release pressure, but that is because the regulator would weigh less due to a weaker gravitational field, not because the PC is in a vacuum.
If the PC were a semi-flexible container, then yes, outside pressure would make a dramatic difference.
Water boils at a lower temperature in an unsealed pot because there is less atmospheric pressure. But the PC develops its pressure by lifting a weight. The difference in the weight of the regulator between 5000 feet, and sea level is negligable, and so the internal pressure of the pot should be the same regardless of the elevation you are cooking at.
I concur with the post that suggests a poor seal between the lid and the pot, or maybe a faulty pressure valve, if your PC has one.
In answere to GG's question, I sometimes cook my rice on the stove top, in a covered pot, sometimes in the rice cooker, and sometimes in the PC, depending on other factors. The PC is not any more work than the other methods, and shortens the cooking time required, which can free me to get other things done, as that burner is available to me for reuse sooner.
Why, I've even been known to pre-cook my rice, and heat in later in the microwave.
There are valid reasons to use the PC, just as there are valid reasons to cook a specific rice pilaf that we make on the stove top rather than in the oven, in a casserole dish as the recipe was first given to us. Sometimes though, using the casserole dish is the better choice, again, depending on other factors. And the cookinhg period from removing the PC to opening the lid, when I place the unopened PC under cold running water is less than 30 seconds, litteraly.
To know many techniques is to allow greater creativity, and better time management. It gives you flexibility.
Oh, one thing that will affect time is outside ambient temperature. The cooler it is in your home, the more time that will be required to bring the PC up to sufficient temperature to develop the required cooking pressure, and more energy will be required to keep it there. The pot radiates heat, as well as absorbing it. The greater the difference between the temperature of the metal, and the air, the faster the pot will radiate heat from the pot.
Seeeeeeeya; Chief Longwind of the North
, and I of course need it for many many kinds of meal, so I still have to look for the best solution for me, even if it consist of buying a new cooker, that's why I asked the brand of cooker all of you use. But I sincerely thank your help and opinion, and the other's,.
