Making Herman the German starter using brown sugar
I'm not sure but I think brown suger can also be used to make a Herman. The Herman dough consists of Lactobacillales and yeast. Both need sugar to live. White refined sugar mostly consists of saccharose (99,96 % saccharose, 0,04 % inverted sugar syrup).1 Brown sugar is nothing else than white sugar mixed with molasses. 2 Therefore I assume that you can use brown sugar instead of white sugar. Due to the molasses in the brown sugar you might use a bit more brown sugar than the receipe says for the white sugar. Wikipedia says that "Based on total weight, regular brown sugar contains up to 10% molasses.". I think, about 10% more brown sugar and it will be fine. 


1 German Wikipedia article about (the purity levels of) sugar says "Raffinade ist der kristallisierte schneeweiße Zucker mit dem höchsten Reinheitsgrad (99,96 % Saccharose, 0,04 % Invertzucker).", translated: "Refined sugar is the crystallized, snow-white sugar with the highest level of purity (99,96 % saccharose, 0,04 % inverted sugar syrup).

2 English Wikipedia article about brown sugar