The base of this full-flavored gravy is a stock that includes the turkey's giblets, wing tips, and neck. Start the gravy as the rolled turkey is browning.
Heat 2 tablespoons oil in a medium saucepan over medium heat. Brown wing tips, neck, and giblets, about 3 minutes per side, and transfer to a plate. Add remaining tablespoon oil to saucepan. Cook celery, onion, and carrot, until lightly browned, about 5 minutes. Add wine and simmer, stirring and scraping up browned bits from bottom, until liquid has reduced by half, about 2 minutes.
Return wing tips, neck, and giblets to pan along with 4 cups water, celery seeds, peppercorns, bay leaf, parsley, thyme, and sage. Bring to a boil. Reduce heat and simmer, covered, for 1 hour. Strain stock through a fine sieve; discard solids.
Wipe out saucepan. Reduce heat to low. Melt butter and add flour and cook, stirring occasionally, for 3 minutes (do not let flour brown). Gradually whisk in 3 cups warm stock. Simmer until thickened, about 15 minutes. Season with salt.
Storage: Gravy can be refrigerated up to 3 days.