A pressure cooker is a fast way to cook great northern beans, which will cook up to 10 times faster than by regular cooking methods. Pressure cookers work by slowing the escape of steam from boiling liquids inside the pot. The steam increases pressure inside the pot, and the pressure level is maintained by a vent in the top of the lid that is covered by a weight. Excess pressure is released through a vent on the top. The vent is covered by a weight that allows excess steam to escape and maintains the pressure inside the cooker.
Wash one cup of dry beans in cool water. Pour clean beans into a large plastic bowl. Cover the beans with cool water and place in the refrigerator overnight or for eight hours.
Pour the water off the beans after soaking overnight. Rinse the beans with cool water. Add the beans to the pressure cooker.
Pour four cups of cool water over the beans. Add one tbsp. of vegetable oil to the water. Place the lid on the pressure cooker and turn until it seals.
Place the pressure cooker weight on top of the vent hole in the top of the lid. Heat the beans in the cooker over medium heat until the weight jiggles steadily. Cook for eight to 12 minutes after the weight begins to jiggle.
Turn the heat off after no more than 12 minutes. Wait for the weight on the lid to stop jiggling. Wait for one hour to allow the cooker to cool and then carefully lift the entire pressure cooker and place it in the sink.
Turn on the tap and allow cold water to flow over the pressure cooker. Gently lift the weight slightly with a long wooden spoon to release any trapped steam. Turn off the water and then open the cooker lid.
Pour the beans into a regular cooking pot. Add seasonings such as salt and pepper. Simmer for about five minutes. Wash the pressure cooker thoroughly, and make sure to clear the vent hole and rubber gaskets on the lid.
Cook unsoaked beans for 25 to 30 minutes.
Make sure that the vent hole is completely clean and free of any blockage before and after cooking.
Do not omit the vegetable oil for pressure-cooking beans. The oil prevents foaming of the beans and prevents loose skins from clogging the vent.
Never fill a pressure cooker more than two-thirds full.