Put salt, brown sugar and 4 cups water in a large pot. Bring to a boil and cook to dissolve. Add remaining ingredients and allow to cool to room temperature.
Put your rinsed turkey into a brining bag in kitchen sink. Pour brine mixture into bag and over the top of the turkey. Swish everything around so that the turkey is well covered. Squeeze as much air out of the bag as you can and seal it securely with a twist tie or a clip. Put the turkey inside a second plastic bag and place it in an ice chest with ice and water, so bagged turkey is completely submerged. Brine for 12 to 24 hours, turning periodically.