Very sour sauerbraten?

My mother who is of German decent makes sauerbraten from a very old ped down recipe. Using white vinegar and pickling spices and pickling for 5 days. The result is a very powerful concoction that's takes some getting used to. When I go to a German restaurant and order sauerbraten it is good but very mild. I'm wondering if the restaurant recipes are toned down for american tastes like mexican and Chinese food, or is my mothers recipe just strange