Some chopped fresh herbssuch as thyme or parsley; optional
Kosher saltfreshly ground pepper
freshly ground pepper
for the roasted turkey stock
Preheat oven to 450°. Divide turkey parts, onions, carrots, celery, and garlic between 2 rimmed baking sheets. Drizzle with oil, season with salt and pepper, and toss to coat. Roast, turning once, until vegetables are soft and caramelized (they should stick slightly to pans), 45–50 minutes.
Transfer to a large pot and add thyme, bay leaves, peppercorns, and 16 cups water. Pour ¼ cup water into each baking sheet, scraping up any browned bits; add to pot. Bring to a simmer and cook until stock is deep golden brown and reduced to about 12 cups, about 1 ½ hours. Strain into containers. Let cool; cover and chill.
for the gravy
Carefully lift the turkey roasting pan and strain drippings into a small bowl or measuring cup; discard solids. Skim fat from surface, reserving ¼ cup. Add drippings to stock.
Set roasting pan over 2 burners set to medium-high heat. Add wine and cook, scraping up any brown bits, until almost evaporated, about 2 minutes. Reduce heat to medium and whisk in flour and reserved fat. Cook, whisking, until roux is deep golden brown, about 5 minutes.
Whisking, gradually ladle stock mixture into roux and simmer (still whisking!) until thickened; add vinegar. Strain into a medium saucepan if you prefer a smooth texture. Stir in soy sauce and/or herbs, if using; season with salt and pepper. Keep warm until ready to serve.
Stock can be made 3 days ahead. Keep chilled, or freeze up to 3 months.