In a large container, combine the Morton kosher salt and water.
Stir until the Morton kosher salt is dissolved.
If adding sugar, combine it with 2 cups of water in a saucepan. Stir over medium -high heat until the sugar dissolves. (Drop in a few ice cubes if you want to speed up the cooling process.) Stir the sugar water into the brine mixture.
Add the brine solution to the turkey in the food-safe brining bag set in the ice chest. Be sure that the turkey is completely covered in the bag. You can double the brining solution or add additional water.
Tightly tie the brining bag closed and cover it completely with ice. Close the ice chest and place it in a cool place. Periodically check that the ice chest is still cold and add more ice if needed. You can turn the turkey over once or twice. Allow the turkey to brine overnight.
Remove the turkey from the brine solution. Discard the brine solution, any herbs, and the brining bag. Thoroughly sanitize the ice chest with a bleach solution.
Pat the turkey dry with paper towels. Place on a platter in the refrigerator uncovered for a few hours until ready to roast. (This will help make the turkey skin crisper.)