My own experience with pressure cookers dates from the mid-1980s, when my mom brought a pressure cooker back from India and proceeded to turn out curries and dals in less than 10 minutes. I was impressed. Something of a junk-food vegetarian, I saw that I could incorporate homemade lentil soup, chickpeas and wheat berries into my diet without spending hours in the kitchen. I have pressure-cooked almost daily ever since, and I'm still impressed with what my cooker can do.
Here's how the pressure cooker works its magic: When the tightly sealed cooker is set over high heat, steam pressure builds and the internal temperature rises, increasing the boiling point from the standard 212° to 250°. Under high pressure (about 15 pounds per square inch), the fiber in food is tenderized and flavors mingle in record time. What's more, fewer nutrients are lost because cooking is so speedy and because nutrient-rich steam condenses in the pot instead of being lost in the air.
Although I use my pressure cooker for beans and grains and dense vegetables, it also makes quick work of tenderizing meat. A three-pound pot roast is ready in an hour.