Bread is made of flour, water, salt, and yeast and nothing else.

Dear wanker, allow me to hold your face under the putrescent waters of knowledge and let me name UH about every German bakery in existence who deems to disagree. And, if I may say so, every German, period. As a whole they are obsessed with bread and I've yet to meet one who minds some ZOMG WRONG ingredients like seeds, quark, milk products in general, sugar, potatoes, eggs and so on and so forth in their bread.

I personally very much dig rye bread with quark. And, also, Butterbrot.