piimäjuuri
Piimäjuuri, also known as sourdough starter or leaven, is a cultivated mixture of flour and water containing a symbiotic culture of wild yeast and lactic acid bacteria. This starter is used to leaven bread and other baked goods, imparting a characteristic tangy flavor and improved texture. The microorganisms in piimäjuuri ferment the flour, producing carbon dioxide gas which causes the dough to rise, and lactic and acetic acids which contribute to the sour taste and act as natural preservatives.
The process of creating and maintaining piimäjuuri typically involves repeatedly feeding the starter with fresh flour