Lievito Naturale

Among professional bakers in Italy, actual yeast is often not used; a kind of sourdough known as lievito naturale or lievito madre (natural yeast or mother yeast) is used in its place. These natural yeasts are products of a natural fermentation of flour and water (sometimes naturally yeast-ridden foods, such as grape skins or hops, are used to begin a natural yeast) and contain certain acids and enzymes that also promote long-standing freshness in the pastries they leaven. As the natural yeast is used, a little is saved and more flour and water are added to renew it and make a sufficient quantity for the next use. Such is the cult of natural yeast in Italy that when Italian bakers travel, they take some of their precious natural yeast with them. When the great commercial establishments finish the last of their natural yeast before closing for annual cleaning, a competitor will contribute a bit from which to start a new batch upon reopening.