Sour cereal soup

Sour cereal soup is a Slavic traditional soup made with various types of cereals such as rye, wheat and oats, which are fermented to create a sourdough-like soup base and stirred into a pot of stock which may or may not contain meat such as boiled sausage and bacon, along with other ingredients such as hard-boiled eggs, potatoes and dried mushrooms.

The most notable, żur (also called żurek, zalewajka, keselica or barszcz biały), is considered a part of the national cuisine of Poland. Made with soured rye flour (sourdough starter), sometimes also with soured oatmeal, bread or wheat, it has a characteristic slightly sour, thick and tangy taste, and is served hot.

Sour cereal soup can be also found in Lithuanian, Ukrainian or Belarusian cuisine (as žur, kiselycia or kisialica), a reminiscence of all these countries' current territory being once in the Polish–Lithuanian Commonwealth. Though it is also prepared in the mountainous regions of Bohemia in the Czech Republic, where it is known as kyselo.