Sour cereal soup

Sour cereal soupis a Slavic traditional soup made with various types ofcerealssuch asrye,wheatandoats, which arefermentedto create asourdough-like soup base and stirred into a pot of stock which may or may not containmeatsuch as boiledsausageandbacon, along with other ingredients such as hard-boiled eggs,potatoesand dried mushrooms.
The most notable,żur(also calledżurek, zalewajka,keselicaorbarszcz biały), is considered a part of the national cuisine ofPoland.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 inLithuanian,UkrainianorBelarusian cuisine(asžur,kisjalicaorkiselycia), a reminiscence of all these countries current territory being once inCommonwealth of Two Nations.Though it is also prepared in the mountainous regions ofBohemiain theCzech Republic, where it is known askyselo.
Żur(Polish:żur,diminutive:żurek) is a soup made ofsouredrye flour (akin to sourdough) and meat (usually boiled porksausageor pieces of smoked sausage,baconorpork ribs).
The recipe varies regionally. In Poland it is sometimes served in an edible bowl made of bread or with boiled potatoes. InSilesia, a type of sour rye soup known asżur śląskiis served in a bowl, poured over mashed potatoes. In thePodlasieregion and also elsewhere in Poland, it is common to eatżurekwith halved hard-boiled eggs.  InPolish Subcarpathia, there is a traditional variety made of fermented oatmeal (Polish:żur owsianyorkisełycia). In Polandżurekis traditionally eaten atEaster, but is also popular during other parts of the year. It is sometimes flavored with bits of sausage, usually eaten with bread or buns.
Another similar soup, sometimes identified as identical with żur – but usually differentiated by its preparation with souredwheat flourrather than rye, is known asbarszcz biały(lit. 'whitebarszcz'). According to some regional traditions, żur is the lenten variation containing no meat and served with additions such as hard-boiled eggs and boiled potatoes, while barszcz biały is a variant with meat such as sausage and bacon.
The following ingredients may be used:
In Belarus,žur(Belarusian:жур) orkisjalica(Belarusian:кісяліца) is a soup made of fermented oatmeal or rye.Žurmay also denote a thicker porridge, a type ofkisselmade of fermented oatmeal, which is known since the times ofKievan Rus'.
Kyselo(Czech:kyselo, krkonošské kyselo;German:Kübelsauer) is a soup based onryesourdoughandmushrooms.It is a traditionalCzech cuisinefrom poor folk food originating in the NorthernBohemiahighland region of theGiant Mountains.It is very substantial and it contains an abundance ofproteins,B vitamins,dietary fiberand other importantnutrients.
Kyselo has been a traditional daily food of poor people in the Giant Mountain region for centuries, primarily in the winter.It is made from locally accessible, cheap, storable ingredients (the mushrooms are usually used dried) and nutritious ingredients so it provides substantial energy for hard mountain life and work.Historically kyselo was made without eggs.  Eggs in early times were produced mainly for sale on the market, not for one's own family, so eggs were only eaten on some holidays.Potatoes became widespread among poor people ofCzech landsin the late 18th century, so before that time soups of this type were also made without potatoes.
Usage of sourdough indicates that kyselo has ancient origins, probably inmedieval(andprehistoric)fermentedcerealporridges.The Giant Mountain region is on the Czech–Polish border, and kyselo is a close relative of the Polish sour rye soup.
The wordkyseloisderivedfrom the Slavic word ( Polish, Słowak, Czech) „kisić” „to make sour”,kyselý, which means 'sour' inCzech.  The sourdough which kyselo is made from is called "chlebový kvásek" or "chlebový kvas" (not to be confused with the Russiankvass).
Sometimes another sour mushroom-based Czech soupkulajdaor its variants are mistakenly calledkyselo.The difference is thatkulajdaand similar soups do not use sourdough butsour creamor milk and vinegar.  To reduce this misunderstanding, kyselo is often calledKrkonošské kyselo("Giant Mountain Kyselo").
In Eastern regions of the Czech Republic and inSlovakiathere is a soup calledkyselica, but it is a variation ofsauerkrautsoup.
The basis of kyselo is strongbrothmade from mushrooms andcarawayin water. Central Europeanmushroom speciessuch ascepand similar ones are used. The mushrooms are usually used dried in the winter.The broth isthickenedby sourdough which should ideally be made fromryeflour. Families in the Giant Mountains would brew their sourdough base in cookware called "kyselák" or "kvasák".The thickened broth is supplemented by onionsautéedin butter,boiledand thenroastedpotatoes andscrambled eggsand seasoned with salt andvinegar.Due to its ancient origins, kyselo has no fixed recipe, and the preparation is a little different in every family. The recipe is passed on byoral tradition. There are local variants of kyselo in the Giant Mountains: without eggs or withhard-boiled eggs, boiled but not roasted potatoes, with or without cream, etc.
Instant powderkyselo base is now available for use in large catering kitchensor liquid fermented cereal
Kyselo is sometimes served in an ediblebread bowl.Garnishes ofscallion,parsleyor other green herbs can be used. The potatoes are often served on a plate for diners to help themselves.Usually salt and vinegar are also on the table for personal seasoning preferences. Kyselo is filling so is often served as a main course.
As a staple food, kyselo plays an important part in local legends and fairy tales, especially in connection to the mythical mountain lordKrakonoš(German:Rübezahl).  It is said that he gave sourdough to people and invented kyselo.In the Giant Mountains there is also a peak called theKotel(Polish:Kocioł, German:Kesselkoppe) which meanscauldron.  When fog rises from the valley at bottom of Kotel, people say that Krakonoš is cooking the kyselo.
The namekyselois well-known throughout the Czech Republic because ofVečerníčekchildren's television seriesKrkonošské pohádky(Fairy Tales from the Giant Mountains), in which Anče, one of the main characters, cookskyseloin almost all of the episodes.
Eastern European cuisinesalso have variations of soups based on soured flour or other modes of fermentation. Examples areRussianokroshkamade withkvass,Romanianborșmade of fermented wheat or barley bran along withciorbă, andFinnishhapanvellisoup is made withpeaand sour dough. A more distant relative isJapanesemiso soup, which also uses a fermented basic ingredient –miso paste.