Combine first 7 ingredients in a large heavy-duty, zip-top plastic bag; add fish, and seal bag. Toss to coat well; marinate in refrigerator 1 hour.
Remove grouper from marinade; reserve marinade.
Place marinade in a saucepan. Bring to a boil; remove from heat. Coat grill rack with cooking spray. Cover and grill grouper over medium-hot coals (350 to 40
minutes on each side or until fish flakes easily when tested with a fork, basting occasionally with reserved marinade.