Bread is food made out of flour, water, salt and it may include other ingredients depending on the kind of bread. During its elaboration it goes through several processes such as kneading and fermentation, and it is cooked in an oven. Fermentation is the key that gives bread its particular taste and characteristics. The discovery of fermentation is attributed to the Egyptians. They elaborated a type of flat bread made out of millet and barley, which was cooked over heated stones, apparently after leaving an uncooked piece of dough they noticed that the dough was sour, this dough is now known as sourdough.El pan es un alimento hecho con harina, agua, sal entre otros ingredientes dependiendo del tipo de pan, en su elaboración pasa por un amasado, fermentación, y su cocción es en horno. La fermentación, es la clave del sabor y características del pan, se atribuye que los precursores de la fermentación fueron los egipcios, cuando elaboraban un tipo de tortillas de mijo y cebada, cocidas en piedras calentada y al parecer, al dejar un pedazo de masa sin cocción notaron que se transformó a una masa agria, que ahora se conoce como masa madre.