1 can (6 ounce) frozen apple juice concentrate, thawed
1/4 cup ketchup
2 tablespoons packed brown sugar
1 tablespoon cider vinegar
1 teaspoon dried thyme
1/8 teaspoon hot-pepper sauce
6 boneless, skinless chicken breast halves (4 ounces each)
The night before:
In a small saucepan, combine the apple juice concentrate, ketchup, brown sugar, vinegar, thyme and hot-pepper sauce. Cook, stirring, over medium heat until the sugar completely dissolves. Remove from the heat and cool to room temperature. Place the chicken in a single layer in a 13-by-9-inch baking pan, or in a large ziploc bag. Pour about half of the cooled ketchup mixture over the chicken, turning once to coat both sides. Cover and refrigerate both the chicken and the remaining ketchup mixture until the next day.
Coat a grill rack with nonstick spray before adding chicken. Grill chicken breasts over medium-hot coals until done, basting occasionally with the reserved apple-ketchup mixture.