Keep in mind that the times given in the charts are only for the time the food is cooked under pressure. Once the lid is locked firmly and securely into place, it can take 5 to 40 minutes for the pressure itself to build. The time it takes for the pressure to build depends on a number of factors: how well your particular pressure cooker conducts heat, the burner setting, the amount of food in the pressure cooker, and the temperature of that food. For example, colder or frozen ingredients in the pressure cooker will affect the temperature of the liquid you add and will take longer to come to pressure.
The time required to pressure cook beans can depend on the beans and how dry they are. How the beans are stored, or even the humidity during the time the beans are exposed to the air, can lengthen or shorten their cooking time.
Getting beans ready to cook begins with going over them and discarding any broken or shriveled beans. Also, always rinse and drain the beans before you soak or cook them.
As a general rule, you'll want to cook each cup of beans in 4 cups of water or broth and 2 teaspoons of oil. The oil is necessary to prevent foaming, which can clog the pressure cooker regulator. You can add other ingredients—like herbs or vegetables—along with the beans, but don't add salt until after the beans are cooked because it will hinder the cooking.
Soaking beans in water overnight removes much of the sugar molecules (specifically the oligosaccharides raffinose and stachyose) that cause excessive gas and other digestive problems for many people. Anise seeds, coriander seeds, and cumin are often added to bean dishes because they're natural carminatives, or additives that reduce the formation of or aid in the expulsion of digestive gas.
Regardless of whether you presoak the beans or cook them immediately, it's generally best to err on the side of undercooking them. If necessary, you can finish cooking them by simmering them in the cooking liquid. For most dishes, beans should be cooked until they're tender, not mushy.
Rice and Grains
As a general rule, when prepared in the pressure cooker, rice and grains cook best in a large quantity of liquid. A combination of natural and quick pressure release is then used to finish the cooking. If further cooking is needed once the rice or grain has been stirred and fluffed, simmer until tender. Once rice or grains are cooked to the desired result, the excess liquid is drained. Keep in mind that rice or grains should be slightly undercooked if they'll be added to soups, stews, or casseroles.
White Long-Grain or Basmati Rice
Long-grain white rice and basmati rice require different cooking methods than other types of rice or grains. Also, when they're cooked in the pressure cooker, these types of rice will be slightly stickier and moister than when they're cooked on the stovetop. Cook the rice on high for 3 minutes and then remove the pressure cooker from the heat and let the pressure release naturally for 7 minutes. Quick-release any remaining pressure before removing the lid.
When cooking white long-grain or basmati rice, do not fill the pressure cooker more than half full. The butter or oil is necessary to prevent the rice from foaming, which can clog the pressure cooker's pressure regulator.
Other Types of Rice and Grains
In most cases, 1 cup of rice (other than white rice) or grain is cooked in 3¼ cups of liquid along with 1 tablespoon of butter or oil.
When you cook vegetables in the pressure cooker, you'll need to add at least ½ cup water or other liquid along with the vegetables so that the cooker will come to pressure. Vegetables should always be well washed. Unless indicated otherwise in the table, peeling is optional.
Quick pressure release is used for all vegetables. Because they cook quickly, it's better to err on the side of caution and undercook the vegetables and then cover them and let them steam to finish cooking.
If you're pressure cooking unthawed frozen vegetables, add 1 or 2 minutes to the cooking time.
The longer you intend to pressure cook meats, the more liquid you'll need to add to the pressure cooker. For example, for most cuts of meat you'll need to add at least 1 cup of liquid if you'll be cooking the meat for 45 minutes or less, or at least 1½ cups of liquid for longer cooking periods.
Times given are an approximation. If there is any doubt as to whether the meat is cooked through, use a meat thermometer to determine the internal meat temperature.