When I smoked that last shoulder I had a foil pan under it to catch the drippings. I chilled that liquid so I could more easily separate the fat from the juices. I used all the fat to make a thick gravy. It took a lot of flour to make the roux so the gravy set up tight in the fridge. With a spider, I dipped the cooked potato pieces from the cooking water and used that starchy water and a whisk to bring a big spoonful of that cold gravy concentrate back to life. I really should freeze the rest of it.