German Cream of Tomato Soup

1 lb. can stewed tomatoes
2 1/2 heaping cups grated raw potatoes
1 1/2 c. chopped onions
2 tbs. butter
2 c. water
1 tsp. sugar
1 tsp. salt
1/2 tsp. savory or marjoram
1/4 tsp. pepper
1/4 tsp. baking soda
3 c. milk

Combine first 9 ingredients (tomatoes through pepper) in large pot. Cover, simmer about 40 min. or until potatoes are tender. Add soda and milk. Heat, stirring. Do not boil.