Tip: Any liquid you use will add some hint of flavor to the outide of your ribs. The liquid doesn't penetrate the meat during the cooking process. In fact, your pressure cooker will remove liquid from your meat during the cooking process and those natural juices will also steam in your pot and flavor your ribs. The best way to impart flavor to your ribs is to use a dry rub and let your meat sit overnight. I usually do 10-24 hours, but you can even leave them as long 48 hours with the rub on.