But quite a few older generation Polish people have food that was prepared by their Mothers and depending where they lived, depends on the variation they are used too.
well, you are right and when it comes to soup base for beet soup and zurek, traditionally women in those days used to make a fermented base, so the taste was naturally sour and I actually think is is healthy for you.
Nowdays, in order to achieve the sour taste, people use leon juice or other things, but it is not the same. I think that respected cooks still use the fermented base because I have seen some recipes being revamped in Polish magazines, it just doesn't happen that often. It is the same with bread such a sour dough bread which calls for the fermented base as well, because it makes a huge difference in taste but it is time consuming.