Place the soaked beans and their soaking liquid in a pressure cooker. Add the bell pepper, garlic, and bay leaf to the pot. Lock the lid into place and set the petcock on the vent pipe. Place the cooker over medium-high heat; bring to full pressure and cook for 20 minutes (or follow the manufacturer’s directions for your own pressure cooker). Remove the cooker from the heat and allow the steam to dissipate. After about 15 minutes, with your hand protected by an oven mitt, carefully lift off the petcock. If no steam comes out of the vent, carefully remove the lid. If there is still steam emerging, wait until it stops before opening the cooker.