Combine all the ingredients in a large pot. Stir until the sugar & salt dissolve. Bring the mixture to a boil, then turn off the heat & allow to cool.
Once the brine has cooled completely or at least to room temperature, lower in your turkey (or chicken). Or, if your bird is too large to fit in your pot - pour the brine into a 5 gallon food safe bucket, a cooler, or a large brining bag. Refrigerate for 16-24 hours.
Discard the brine, & soak the turkey in cold water for 15 minutes. Then, dry the turkey inside & out. Roast as normal.