Pick over beans, rinse and drain. Be sure to not fill the pressure cooker above the halfway mark. Combine ingredients in the cooker and cook for 22 to 25 minutes. For firm cooked beans, check for doneness after minimum time indicated. For soft cooked beans, add 2 extra minutes under high pressure. When cooking time is up, quick release pressure by placing cooker under cold running water. Drain immediately. Always clean the lid and vent thoroughly after cooking beans.
Optional presoak: Cook the beans under high pressure for 1 minute, using 4 cups of water per cup of dried beans. Quick release the pressure under cold running water, drain and rinse the beans. Always discard any loose or free floating bean skins before further cooking. Follow cooking instructions above but adjust cooking time to 7 to 10 minutes.
Add 3 cups of water and 1 tablespoon of oil for each additional cup of beans.
Recipe courtesy of Lorna Sass, author of Cooking Under Pressure