Before the use of brewer’s yeast for fermentation stage, a dough formed as a mix of water, wheat or rye and raisins, prunes and bran, had been left soaking as a first fermentation. Then, an initial alcoholic fermentation started and after a few days of cultivation an acidic fermentation triggered. After several refreshes, this sourdough was added to the dough. From the latest batch a piece of dough was put away, and after two or three refreshments, spaced each 4 or 5 hours the natural yeast was obtained. "Dough" ready to use, in a proportion of 30 to 40 kilos dough per 100 kg. flour. The baker had to pay special attention in the development of this ferment/sourdough, because it depended on getting good quality bread. At present time, therefore, the fermented dough has lost its basic function of serving as "yeast seeding ", as this objective is achieved conveniently with the addition of yeast, focusing on other objectives. In a few words we could resume that as biotechnology has
progressed it is possible to bake without the use of sourdoughs, but this is a relatively recent development.