Yeast
By: Anonymous

About

Yeast is a form of Fungi used that has been used for centuries for levening in baking and fermenting alcohol.

Information
Other names: action yeast, top yeast, brewer's yeast
Translations: Raugs, Mielės, Drojdie, Kvasac, Men, Drożdże, Gist, खमीर, Levedura, Дрожжи, Ζύμη, خميرة, 누룩, Droždí, Квасац, Lebadura, 酵母, Llevat, Kvas, Droždie, Lievito, שמרים, Jäst, Ragi, 酵母, Levure, Hefe, Gær, Gjær, Levadura, Дріжджі, Hiiva, Мая


Physical Description
Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with the 1,500 species currently described estimated to be only 1% of all yeast species. Most reproduce asexually by budding, although a few do so by binary fission.Yeast size can vary greatly depending on the species, typically measuring 3–4 µm in diameter, although some yeasts can reach over 40 µm
Colors: whitish to light brown


Tasting Notes
Flavors: bitter  
Mouthfeel: Grainy
Food complements: Flour, Beer


Selecting and Buying
Seasonality: january, february, march, april, may, june, july, august, september, opctober, november, december
Buying: Today there are several retailers of baker's yeast; one of the best-known in North America is Fleischmann’s Yeast, which was developed in 1868. During World War II Fleischmann's developed a granulated active dry yeast, which did not require refrigeration and had a longer shelf life than fresh yeast. The company created yeast that would rise twice as fast, reducing baking time. Baker's yeast is also sold as a fresh yeast compressed into a square "cake".


Preparation and Use
Alcoholic beverages are defined as beverages that contain ethanol (C2H5OH).Beverages such as wine, beer, or distilled spirits all use yeast at some stage of their production.Yeast, most commonly Saccharomyces cerevisiae, is used in baking as a leavening agent, where it converts the fermentable sugars present in dough into the gas carbon dioxide. This causes the dough to expand or rise as gas forms pockets or bubbles. When the dough is baked the yeast dies and the air pockets "set", giving the baked product a soft and spongy texture. The use of potatoes, water from potato boiling, eggs, or sugar in a bread dough accelerates the growth of yeasts. 


Conserving and Storing
Yeasts are able to grow in foods with a low pH, (5.0 or lower) and in the presence of sugars, organic acids and other easily metabolized carbon sources. During their growth, yeasts metabolize some food components and produce metabolic end products. This causes the physical, chemical, and sensible properties of a food to change, and the food is spoiled. The growth of yeast within food products is often seen on their surface, as in cheeses or meats, or by the fermentation of sugars in beverages, such as juices, and semi-liquid products, such as syrups and jams.


Social/Political
The word "yeast" comes to us from Old English gist, gyst, and from the Indo-European root yes-, meaning boil, foam, or bubble.Yeast microbes are probably one of the earliest domesticated organisms. People have used yeast for fermentation and baking throughout history. Archaeologists digging in Egyptian ruins found early grinding stones and baking chambers for yeasted bread, as well as drawings of 4,000-year-old bakeries and breweries.
History: By the late 1700s, two yeast strains used in brewing had been identified: Saccharomyces cerevisiae, so called "high" or top yeast, and S.  carlsbergensis, "low" or bottom yeast. High yeast was sold commercially by the Dutch for bread making starting in 1780, while around 1800, the Germans started producing S. cerevisiae in the form of cream. In 1825 a method was developed to remove the liquid so the yeast could be prepared as solid blocks