Cook potatoes in salted water. When half done, add beans, vinegar, pepper and garlic (spear on toothpick for easy finding). Add onion. Simmer until potatoes are done. Remove garlic glove.
Combine the flour and 1/4 cup water and make a smooth paste. Thicken soup with the flour paste.
Remove from heat. Slowly stir in sour cream. Do not cook any further. Stir in cooked and diced Mettwurst or other German sausage just before serving.
