http://www.durgan.org/URL/?BDUGG 18 April 2012 Pressure Cooker
Pressure cookers have got a bad name, since when cooking items like peas and beans the rocker hole can get plugged from small particles like skins bubbling up blocking the exit, pressure builds up and the safety valve blows and scares people away. When the safety valve blows there is as miserable mess to clean up, usually from the ceiling of the kitchen.
To eliminate the blocking problem, I use a colander with the handles knocked off. Handles are knocked off with a sharp blow from a hammer, since they are only spot welded. When inserted into the pressure cooker, there is about two to three inches for the water, which doesn’t touch any food placed in the calendar, hence the items are steam cooked, and no bubbling occurs. My colander has been in operation for over 20 years. I have also used the all steel butterfly steam device with feet. It is equally as effective.
The gasket should last for the life of the pressure cooker if a film of vegetable oil is applied to the metal surface, where the gasket sits prior to use. Also the lid should never be used loose to cover the pot, since heat builds up and destroyes the gasket. The pressure cooker may be used as a boiling pot, but never use the gasketed lid as a cover.
The best cooker on the market is the Presto, since it has a dead simple effective closing mechanism. Some of the new types now on the market are complicated with silly elaborate safety devices which are a recipe for trouble down the line, and serve no real purpose.
One more caveat. The bottom of the pot can get warped if placed on high heat with no water, or the water gets all evaporated. If this occurs the pot will not sit flat on the heating surface. There is a bulge.
To finish off a roast or some other products, I do the cooking in the pressure cooker and add any condiments or whatever in another pot to complete the cooking process. In other words all the pressure cooker contains is the product and water for steam cooking.
When beginning the cooking process, let all the air out of the cooker by operating for five or ten minutes without the rocker in place, then apply the rocker for the appropriate cooking time. Air inside the cooker will create an insulation and uneven cooking.
I have experienced all the problems mentioned at one time in my life, so my comments are from very practical experience.