8-12 hours before you plan to start cooking the beans, rinse them in strainer and remove any debris.
Once rinsed, cover the beans with 2 inches of filtered water and let soak for 8-12 hours. Add more water throughout the soaking period if needed.
Once the beans have soaked for 8-12 hours, pour the beans and remaining soaking water into the pot of the pressure cooker.
Add the chopped tomato, cilantro, onion (optional), and bacon to the pressure cooker pot. Then add the salt, white pepper, and cumin. Stir to combine ingredients.
Add additional water to the pot to cover the beans by approximately 1-2 inches (or to suit your preference). More water will result in a souper pot of beans, and less water will result in a thicker pot of beans.
Lock the pressure cooker lid into place, and turn the valve to "pressure". Turn the stove heat on high and wait for the pressure indicator button to pop up. Once the pressure indicator has popped up, reduce the heat to medium and allow to pressure cook for 35 minutes.
Once the 35 minutes have elapsed, release the pressure and check the beans for doneness. They should be completely tender, yet holding their shape. If the beans are still too firm, bring the pressure cooker back up to pressure and cook over medium heat for another 10 minutes or until the beans are tender.
Serve with rice or in burrito bowls or tacos. These leftovers get better each day in the fridge!