For the brine: Combine 8 quarts cold water, the salt, sugar, coriander seeds, fennel seeds, red pepper flakes, garlic, bay leaves, carrots, celery and onions in a large container. Immerse the turkey in the brine and refrigerate for 2 to 3 days.
To prepare the turkey for cooking: Remove the turkey from the brine the night before roasting and pat it thoroughly dry with paper towels. Combine the butter, rosemary and some salt in a small bowl. Taste it to make sure it tastes good. Work the butter under the skin of the turkey and massage it into the breasts and the legs. Massage the butter on the outside of the skin as well. Tie the legs together and over the breast so they will protect it during cooking to help keep it moist and juicy. Place the turkey on a sheet tray and refrigerate overnight UNCOVERED! Yes, that's right, uncovered. This will help the skin dry out and become really brown and crispy. Pay close attention not to have any food that will not be cooked near the turkey in the fridge.
Thanksgiving Day: Take the turkey out of the fridge 1 hour before placing in the oven.
Preheat the oven to 450 degrees F.
For the gravy: Place the garlic, celery, onions, celery root, fennel, bay leaves, sage and thyme in a roasting pan and season with salt. Put the chicken stock and wine in the bottom of the roasting pan and place the turkey on top.
Put the turkey in the oven until the skin of the turkey gets really nice and brown, about 40 minutes. Lower the heat of the oven to 350 degrees F for the remainder of the cooking time. Baste the turkey every 30 minutes or so and add more stock to the roasting pan if needed. Think about 17 minutes per pound for the turkey. Tent the turkey with aluminum foil when it gets to the proper color to prevent it from getting too dark.
Remove the turkey from the oven when a thermometer inserted in the thickest part of the turkey reads 160 degrees F. Be sure the thermometer is not touching a bone when doing the reading.
When the turkey has reached the proper temperature, remove it from the roasting pan and let it rest for at least 30 minutes. Cover loosely with aluminum foil.
To finish the gravy: Remove the bay leaves, sage and thyme and from the roasting pan. Using an immersion blender, blend the veggies together until smooth. Taste and adjust the seasoning if needed (it will).
Carve the turkey, and don't fight over the drumsticks.