I always waited for this:
Our state is full of springs with mineral water. Best known is probably the nearby Selters or how it is written in english Seltzer.
Also a long history in our state is to marinate beef, mainly with milk acid bacteria. But as our name Sauerbraten says: the result is sour. I use to do my own marinate made from fruit wines, dried herbs and fruits, ... But I want the sour taste to make the taste of wild boars less strong.
But steaks are different. You want them soft but not sour. So a butcher tried marinating without the sour tasting testing several slightly acid mineral waters from local springs.
Finding the right water was hardest he said. It needs the right mix of minerals and acid.
https://www.youtube.com/watch?v=jKhQBU106eY