1. Wash turkey in hot water; pat dry with paper towels, and chill.
2. Place 4 quarts water, salt, and next 9 ingredients in a large stockpot over medium-high heat. Bring to a boil; reduce heat to low, and simmer 30 minutes. Let cool 3 hours. When cool, add turkey to stockpot or place turkey and brine in brining bag, and chill 1 to 2 days.
3. Preheat oven to 300°. Remove turkey from brine, and pat dry. Rub with olive oil, and roast at 300° for 3 1/2 hours or until internal temperature taken in the thigh registers 170°, basting every 30 minutes. Remove from oven, cover with aluminum foil, and let stand 30 minutes before slicing.
Talking Turkey: Heritage Breeds. In the early 1900s, before the mass production of cheaper (but less tasty) birds, "heritage breeds," such as the Narragansett, Bronze, and Bourbon Red, graced Thanksgiving tables across the country. Heritage turkeys live and forage in the wild and develop larger legs and thighs--and, as a result, richer, juicier meat. They can cost significantly more than a supermarket turkey, but once you've tried one, you won't go back.
To find your own, use an online retailer such as Heritage Foods USA (heritagefoodsusa.com; $129 for an 12-pound turkey, including shipping) or D'Artagnan (dartagnan.com). Or e-mail the American Livestock Breeds Conservancy at firstname.lastname@example.org for a local producer.