It is composed of living beings: microscopic fungi – called yeasts – that feed on sugar, releasing carbonic gas and alcohol. When the dough is heated in the oven, the yeasts multiply, ingesting the sugar and starch contained in the wheat flour. The process is completed with the aforementioned release of carbon dioxide – which is responsible for the rise of the dough – and alcohol, which gives flavor to the bread, cake or pie. Gluten, another element present in flour, makes the dough elastic, allowing the gas exhaled in this reaction to be trapped in small cells inside, making the cake or bread spongy, soft and fluffy. Yeast was discovered by the ancient Egyptians. It was cultivated by the population indoors, but nowadays it is industrialized in a drying process that converts it into powder, making the yeasts inert. By adding water when making the dough, they become active again.
