Wikipedia
Kyselo
Kyselo (or krkonošské kyselo) is a soup based on sourdough and mushrooms. It is a traditional Czech cuisine from poor folk food originating in the Northern Bohemia mountain region Krkonoše. It is very substantial and it contains an abundance of quality proteins, B vitamins, dietary fiber and other important nutrients. Usage of sourdough is closely related to fermented flour usage in the Polish sour rye soup.