Place the potatoes, onion, apple and bacon in a 6-qt. slow cooker. Drain sauerkraut, reserving 1/3 cup liquid; add sauerkraut and reserved liquid to slow cooker., Cut spareribs into serving-size portions; sprinkle with salt and pepper. In a large skillet, heat oil over medium-high heat; brown ribs in batches. Transfer to slow cooker; sprinkle with brown sugar and caraway seeds., Add sausage; pour in beer. Cover and cook on low for 6-7 hours or until ribs are tender.