Wild-Yeast

Food that we are eating can not be distorted with
unknown artificial stuff only to make our metabolisim unnatural,
eventually resulting in a variety of disease.
As you can see from how to get the seed culture,
initially I used pine apple juice(made by crushing it)
and dark rye flour as my teacher, Peter Reinhart, instructed in his book,The Bread Baker's Apprentice.
I can tell you how much sugar or butter is added to make dough.
The answer is "nothing".