Brine: In large saucepan, stir together boiling water, salt and brown sugar until dissolved. Peel zest from orange and lemon; squeeze juice from flesh into salt mixture. Discard flesh. Add orange zest, lemon zest, garlic, bay leaves, thyme, rosemary, sage and peppercorns. Let cool slightly.
In tall large saucepan, or in resealable plastic bag placed inside cooler or large bucket, combine brine mixture with ice water. Let cool completely, about 1 hour. (Make-ahead: Cover and refrigerate for up to 3 days.)
Turkey: Remove giblets and neck from turkey, reserving neck. Discard giblets. Add turkey to brine. Cover and refrigerate for 12 to 15 hours.
Meanwhile, soak 3 cups applewood chips in water for 1 hour; drain.
Remove turkey from brine and rinse under cold water. Discard brine. Pat turkey dry inside and out. Place, breast side up, on greased rack in roasting pan; add reserved neck. Brush turkey all over with oil; sprinkle with thyme, sage and rosemary, pressing to adhere.
For gas barbecue: Heat 1 burner of 2-burner barbecue or 2 outer burners of 3-burner barbecue to medium heat. Seal soaked applewood chips in heavy-duty foil to make packet; poke several holes in top. Place packet directly on lit burner; close lid and let smoke fill barbecue. (For charcoal barbecue: Omit foil and place wood chips directly on coals.)
Place turkey in roasting pan on grill over unlit burner with legs facing centre of barbecue; close lid and cook, basting occasionally and tenting with foil if browning too quickly, until instant-read thermometer inserted in thickest part of breast reads 170°F, about 3 hours.
Transfer turkey to cutting board. Using turkey baster, or tilting turkey with tongs over bowl, remove juices from inside turkey, reserving 1/4 cup for gravy and discarding remainder. Let turkey rest for 30 minutes before carving.
White Wine Gravy: While turkey is resting, remove neck from pan and set aside. Tilt pan so juices collect at 1 end. Skim and discard all but 1/4 cup fat from surface; cook juices in pan and reserved fat over medium heat, scraping up browned bits, for 1 minute. Sprinkle in flour; cook, stirring, until slightly darkened, about 3 minutes. Pour in wine and reserved turkey juices. Gradually pour in broth and 1 cup water, stirring constantly; bring to boil.
Add neck and pepper. Reduce heat to medium and cook, stirring constantly and adding more water if needed to reach desired consistency, until thickened, 7 to 10 minutes. Discard neck. Strain gravy through fine-mesh sieve into serving bowl. Serve with turkey.
Change it up: Oven-Roasted Herbed Brined Turkey
Omitting applewood chips, brine and season turkey as directed. Roast turkey in 325°F oven, basting occasionally and tenting with foil if browning too quickly, until instant-read thermometer inserted in thickest part of thigh reads 170°F, about 3 hours.
Makes 12 to 15 servings.