Start brining the turkey 24 hours before you plan to start smoking it. Make sure that your cooler is clean and dry, and that your drain plug is inserted properly. Or clear space in your refrigerator if you plan on refrigerating the turkey overnight while brining. Spatchcock the thawed turkey.
In a medium sized pot, add 1/2 gallon of apple cider, full can of apple juice concentrate, salt, peppercorns, lemon slices, garlic cloves, cider spices, and all fresh herbs. Bring to a rolling boil over medium heat and allow brining liquid to boil for 60 seconds. Remove the pot from the heat and allow to cool down for about 15 minutes.
Add a 10 pound bag of ice to the bottom of your cooler. Pour in the remaining 1/2 gallon of cold apple cider. Add the warm (but not too hot) apple cider brine to the ice and mix together.
Place the spatchcocked turkey upside down in the cooler, working it around so that it's completely submerged in the brine. Close the lid of the cooler and brine turkey for a full 24 hours. If the outside temperature is colder than your house, keep the cooler outside. You can also open the lid to make sure the ice has not melted all the way and the turkey is still cold (below 37 degrees F) periodically during the 24 hour brining process. Or brine in the refrigerator if you are nervous about the cooler brine.
After 24 hours, remove the turkey from the brine and transfer to a wire cooling rack on top of a sheet tray. Set smoker or charcoal grill to 300 degrees F.
Liberally season all sides of the turkey with your favorite all purpose or citrus seasoning. (I used Heath Riles Simple Citrus Rub and Heath Riles Garlic Butter seasonings).
Insert wireless meat thermometer into the thickest part of the breast to monitor the internal temperature. Smoke turkey at 300 degrees until internal temp in the thickest part of the breast and the innermost area of the thigh and wing reaches 162-165 degrees F. (USDA recommends cooking to 165 degrees F. A 14 pound turkey takes roughly 4½ – 5½ hours to smoke at 300 degrees F, but be sure to check internal temperatures for doneness.)
Remove turkey from the smoker and transfer to a serving platter or cutting board. Allow turkey to rest for 30 minutes before serving.