Humans have been eating leavened breads for over 6000 years, but it was only about 150 years ago that thanks to Louis Pasteur we began to understand the nature of the process. Yeasts are groups of microscopic single-called fungi, relatives of mushrooms. More than 100 different species are known. Some can be dangerous for human health and contribute to food spoilage, others are the key to some of the most amazing foods we consume such as bread, cheese, salumi, wine and beer. One species in particular Saccharomyces cerevisiae whose name means brewers sugar fungus is put to good use in both brewing and baking.
Yeasts today are selected and reproduced industrially, specialist bread makers may also usemother yeast which is spontaneous and has been cultivated over time. These natural yeasts have more complex and unique flavors. This applies to many different preparations, natural spontaneous yeast can be used for wine making, vinegar, cheese, salumi and some typologies of beer. These are only some examples especially found in Italian cuisine but all cultures worldwide, over time have developed their own specialty preparations that involve yeast.