Add the apple juice, brown sugar, and salt into a large saucepan. Over a high heat bring to the boil and stir to dissolve. Once dissolved boil for 1 minute further and remove from heat. Let the mix cool to room temperature and refrigerate until 40°F.
In a very large non-corrosive container, add the remaining ingredients together with the apple juice mixture. Place the turkey into the brine breast side down. If you need to weigh down the turkey with a weight to keep it fully submerged. Set aside in the fridge for 12 - 24 hours (for best results leave for 24 hours).
After 24 hours remove the turkey from the brine. Thoroughly pat dry with paper towels and set on a rack with baking paper below and set in the fridge to air dry overnight. This step is not essential but will give you a nice crispy skin.
Remove the turkey from the fridge. Tie the legs together and fold the wings under the body. Set aside and let rise to room temperature. Now you can start to prepare your smoker.
Fire up your electric smoker and get it to 350°F. Once it starts to produce smoke, turn it down to 230°F and get your turkey in there!
You need to smoke the turkey until a meat thermometer reaches 165°F in the thickest park if the breast. You can use the rule of thumb that your turkey will take around 30 minutes per pound at 230°F (always allow a little bit of extra time just incase)
Once the turkey is cooked remove from the electric smoker and rest for 20 - 30 minutes uncovered.
Carve and serve!