Sauté onion and apple in hot bacon drippings in a Dutch oven until tender. Add sauerkraut, caraway seeds, salt, and water. Bring to a boil. Reduce heat; cover and simmer 1 hour and 15 minutes. Stir in potato; simmer 30 minutes. Cool. Cover and refrigerate overnight.
Serving Suggestions: German Sauerkraut may be served cold or hot with corned beef or frankfurters.