Sourdough Breads Made from a Natural Starter

Most bread is made from a single strain, a clone, of yeast—the kind we buy at the supermarket—while artisanal breads are made from a natural starter that encourages the growth of bacteria and wild yeasts that live in the flour and in the environment. Bread made with a natural starter has a deeper flavor because it contains many strains of yeast. These strains are less aggressive than strains in commercial yeast, so they ferment more slowly and allow more time for the flavor to be extracted from the flour. During this slow fermentation, beneficial bacteria in the air or in the flour take up residence next to the yeasts and create the tangy flavor we recognize in sourdough bread. When the bread is finally fermented, the sourness is controlled by regulating the rising time—the shorter the rise, the less tangy the bread.