I don't know how you defat ... fat.. I wouldn't use it as a base for your sauce. When you pull your pork, if it is dry as you mentioned, you add the fat back into it until it is moist. Then sauce it. Just to be clear, we are not talking about particularly healthy food here! Edit: Also, on a pork butt there is usually a fat cap. Don't remove that, and make sure it is facing up, that will help keep it moist as it renders off.