Make the wine-flavored gravy extra delicious: Scrape up flavorful browned bits from the roasting pan and use some of the drippings. Stir together the cornstarch and chilled wine until smooth before adding to the liquids in the roasting pan.
For the bouquet garni, place thyme sprigs, bay leaves, and parsley stems in the center of a double-thick, 8-inch square of 100-percent-cotton cheesecloth. Bring the corners of the cheesecloth together and tie with clean string.
Place the bouquet garni; onion; wing tips, giblets, and neck; carrot; celery; and water in a large saucepan. Bring to boiling; reduce heat. Simmer, uncovered, very gently for 1-1/2 hours while the turkey is roasting. Cool for 1 hour.
Remove wing tips, giblets, neck, and bouquet garni from the stock; discard. Place the vegetables and cooled stock in a blender container or food processor bowl. Cover and blend or process until nearly smooth (you should have about 2-3/4 cups).
The ideal time to prepare the gravy is while the turkey is standing after being removed from the oven. Place the turkey on a cutting board, preferably one with a ridge to collect the juices. Skim fat from drippings; reserve 3 tablespoons of the fat in roasting pan. While the pan is still hot, pour the pureed stock into the 3 tablespoons fat, scraping all the bits and pieces off the roasting pan with a large wooden spoon or spatula.
Mix cornstarch with cold wine until dissolved. Add all at once to the pureed mixture. Cook and stir over medium heat until slightly thickened and bubbly. Cook and stir 2 minutes more. Season to taste with salt and pepper. Makes about 3 cups (14 servings).