Combine the first seven ingredients; set aside and refrigerate 1 cup for basting. Place one oven roasting bag inside the other. Place turkey inside inner bag; pour in remaining marinade. Seal bags, pressing out as much air as possible; turn to coat turkey. Place in a shallow roasting pan. Refrigerate overnight, turning several times.
Remove turkey; drain and discard marinade.
Prepare grill for indirect medium heat. Tuck wings under turkey and arrange breast side down on grill rack. Grill, covered, for 1 hour.
If using a charcoal grill, add 10 briquettes to coals; turn the turkey. Baste with reserved marinade. Cook, covered, for 1-1/2 to 2 hours, adding 10 briquettes to maintain heat and brushing with marinade every 30 minutes until thermometer inserted in thigh reads 170°. Remove turkey from grill; tent with foil. Let stand 20 minutes before carving.
Conventional roasting method: Follow steps for marinating turkey overnight. Preheat oven to 325°. Place turkey on a rack in a large roaster. Bake, uncovered, 3 to 3-1/2 hours or until a thermometer inserted in a thigh reads 170°. Baste frequently with reserved marinade. When turkey begins to brown, cover lightly with a tent of aluminum foil. Remove turkey from oven; tent with foil. Let stand 20 minutes before carving. If desired, skim fat and thicken pan drippings for gravy; serve with turkey.