There are more than one forms of fermentation; yeast fermentation is probably the most common method. This process is used in many everyday products today. Yeast was first discovered in 1676, but was used before. It has also led to numerous scientific advances. Yeast expands, especially well with a good amount of sugar, the more of the amount the greater it expands. Yeast is a single-celled organism, a fungus to be more specific. They consume carbohydrates, mainly sugars, and produce carbon dioxide and ethanol. They are found in various places, which include: in soil, on plants, in salt water, and even along a digestive tract. Yeast, depending on the type, can reproduce asexually, by budding (and are usually attached and stay that way most of their lives), or sexually, yeast actually form asci that combine with another. Yeast is also used very commonly in baking among other things, some are bread, some cakes, and some drinks. Yeast has a very interesting and unusual way of working and ranges from type to type. In bread the yeast consumes sugar and carbohydrates, producing carbon dioxide and ethanol which is later cooked out, at which point the yeast dies off, at approximately 140° F. In sodas the process is very similar, in which case the carbon dioxide and ethanol becomes carbonation. In alcoholic fermentation there is very little, if at all, oxygen introduced therefore more ethanol is produced, that of which becomes the alcohol. Yeast has an unusual history. It was discovered by a man named Anton Leewenhoek under a microscope. Later, in 1859, Louis Pasteur looked at yeast and officially declared it a single-cell organism. Over 5000 years ago the Egyptians and the Babylonians were using yeast unnoticed. The yeast was hidden in soil, plants, and the air, and they had used that which was unnoticed to make sourdough bread, and the yeast within the various compounds created the rise required for the bread. Yeast has also been used scientifically in a few ways.
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