Sour Cereal Soup

Sour cereal soup is a Slavic traditional soup made with cereals such as rye, wheat or oats fermented into a sourdough-like base and stirred into a pot of stock that may contain boiled sausage and bacon along with hard-boiled eggs, potatoes and dried mushrooms. Its most notable version, zur, also called zurek, zalewajka, keselica or barszcz bialy, made with soured rye flour and sometimes also soured oatmeal, bread or wheat, is considered part of the national cuisine of Poland, and related versions appear in Lithuanian, Ukrainian and Belarusian cuisine as zur, kiselycia or kisialica, a reminder of these countries' shared history in the Polish-Lithuanian Commonwealth, as well as in the mountainous regions of Bohemia in the Czech Republic, where it is known as kyselo.