Fill a large stock pot with water, salt, and brown sugar. Add the smashed garlic cloves. Bring the contents to a low simmer, stirring occasionally, until the salt and sugar have dissolved. Add the herbs and peppercorn. Then, squeeze the juice from the orange and lemon into the pot (don't worry about the pits); place the squeezed orange and lemon into the pot as well. Remove the pot from the heat and let the liquid cool. (Speed up the process by adding ice to the stock pot). Once the brine is cool, carefully place the turkey into it. Or, if you're brining in a different container, transfer the brine to that container and carefully place the turkey into that one. Refrigerate for at least 12 hours, but no longer than 18 hours (again, based on a 12-16 lb turkey. Use the hour per pound rule.) When ready, carefully transfer the turkey from the brine to a large platter or cooking vessel. Rinse it under cold water and pat it dry with paper towels. Season it as you wish, but keep in mind that the turkey is pretty salty as is, so go lightly.