For Chicken Brine
Whisk all brine ingredients in a large bowl until the sugar and salt dissolve. Add chicken. Cover and refrigerate 30 to 60 minutes.
For Fried Chicken
While the chicken brines, stir together flour, corn starch, pepper, salt, garlic powder, onion powder, paprika, baking powder and cayenne pepper in a large bowl. Remove 3/4 cup of the flour mixture to a shallow pan (to use for dredging the chicken). Set aside. Add 3/4 cup cold water to the remaining flour mixture and whisk the batter to thoroughly combine. (if the batter seems to be too thick, add some cold water, no more than 1 tablespoonat a time, until the batter becomes the consistency of pancake batter.)
Heat oil in a large Dutch oven or deep-sided pan over medium heat until it reaches 350°F. Place a wire rack on a rimmed baking sheet.
Remove chicken pieces from the brine; pat dry with paper towels. Discard the brine.
Working in batches, dredge or roll chicken in the dry flour mixture, shaking off any excess. Place chicken in batter and turn to coat. Remove the chicken from batter, allowing excess to drip back into the bowl. Carefully place half the pieces in the hot oil. Adjust the heat as needed to keep the oil between 300° to 325°F. Cook until the chicken coating is a deep golden brown and the internal temperature reaches 160°F for white meat or 175°F for dark meat. This will take about 20 to 25 minutes, depending on the size of the pieces.
Remove from oil and place chicken on wire rack to drain. Bring the oil temperature back to 350°F before repeating with remaining chicken. Serve hot, warm or at room temperature.
Spicy Fried Chicken - Increase cayenne pepper to 1 tablespoon and add 1/4 cup hot sauce (tested with Frank's® Hot Sauce) to batter.
Herbed Fried Chicken - Add 1 tablespoon ground sage, 1/2 tablespoon ground thyme and 1 tablespoon dried rosemary to the flour mixture.