In a large skillet, cook bacon over medium heat until crisp, stirring occasionally. Remove with a slotted spoon; drain on paper towels.

Cook and stir onion in bacon drippings until softened. Reduce heat to medium-low; cook 15-20 minutes or until deep golden brown, stirring occasionally. Add apple and garlic; cook 2 minutes longer. Stir in sauerkraut, mustard, brown sugar and cooked bacon.

Transfer to a 13x9-in. disposable foil pan. Place bratwurst on top. Pour beer over bratwurst. Place pan on grill rack over medium heat; cook, covered, 30-35 minutes or until sausages are no longer pink. Remove pan from heat.

Place the bratwurst directly on the grill. Grill, covered, 2-3 minutes on each side or until browned. Serve on buns with sauerkraut mixture.