Though fermentation has been used by people to produce palatable goods since prehistoric times, no one really knew the cause of fermentation for most of human history. Early scientists, upon the invention of the microscope and the subsequent discovery of yeast, thought that the yeast somehow contributed to fermentation by virtue of its spherical shape rather than any digestive processes. It was believed that the fermentation of foods and fruit juices was the result of molecular vibrations induced by the death of the food's cells.
The acidic byproducts of fermentation give tartness to wine and many foods, such as pickled cucumbers or yogurt. Another byproduct of fermentation that is useful to people is carbon dioxide. Though the gas is poisonous to people, bakers use it to force bread to rise. It is also carbon dioxide that causes champagne to be bubbly and beer to have its distinctive foamy head. It's important to recognize that the alcohol is actually the waste product of fermentation, at least from the yeast's point of view. Generally, yeast won't produce a proper alcohol when exposed to oxygen, despite the fact that the yeast prefer anaerobic processes to aerobic ones as long as there is sufficient sugar present.
However, the processes performed by yeast during fermentation could not be fully understood until the experiments of Louis Pasteur in the 1850s and 1860s. In 1857, Pasteur released the results of his experiments on lactic acid fermentation, which is a type of fermentation that commonly occurs in human muscles when the blood is unable to supply enough oxygen to the muscles during exertion. His results in that experiment proved that this sort of fermentation is caused by living things. During the 1860's, Pasteur devised an experiment in which he filled a specially-crafted bottle full of a broth that should induce fermentation.
Stuck fermentation is an unintentional halting in the fermentation of a substance. Basically, the yeast reaches a point, due to stress factors, that it ceases metabolizing and falls out of the substance. This can be a catastrophic occurrence for the producer because once a fermentation becomes stuck, it is incredibly difficult to start it again because the yeast dies.
On dying, the yeast releases various enzymes that inhibit the further growth of yeast in that particular batch. An example of one cause of stuck fermentation is the use of overripe grapes in wine making. Overripe grapes have a higher amount of sugar in them, and thus the yeast will produce a higher volume of alcohol. If the alcohol level rises above 16-18% ABV, the yeast will probably die, causing the fermentation to be stuck. - 15432
The acidic byproducts of fermentation give tartness to wine and many foods, such as pickled cucumbers or yogurt. Another byproduct of fermentation that is useful to people is carbon dioxide. Though the gas is poisonous to people, bakers use it to force bread to rise. It is also carbon dioxide that causes champagne to be bubbly and beer to have its distinctive foamy head. It's important to recognize that the alcohol is actually the waste product of fermentation, at least from the yeast's point of view. Generally, yeast won't produce a proper alcohol when exposed to oxygen, despite the fact that the yeast prefer anaerobic processes to aerobic ones as long as there is sufficient sugar present.
However, the processes performed by yeast during fermentation could not be fully understood until the experiments of Louis Pasteur in the 1850s and 1860s. In 1857, Pasteur released the results of his experiments on lactic acid fermentation, which is a type of fermentation that commonly occurs in human muscles when the blood is unable to supply enough oxygen to the muscles during exertion. His results in that experiment proved that this sort of fermentation is caused by living things. During the 1860's, Pasteur devised an experiment in which he filled a specially-crafted bottle full of a broth that should induce fermentation.
Stuck fermentation is an unintentional halting in the fermentation of a substance. Basically, the yeast reaches a point, due to stress factors, that it ceases metabolizing and falls out of the substance. This can be a catastrophic occurrence for the producer because once a fermentation becomes stuck, it is incredibly difficult to start it again because the yeast dies.
On dying, the yeast releases various enzymes that inhibit the further growth of yeast in that particular batch. An example of one cause of stuck fermentation is the use of overripe grapes in wine making. Overripe grapes have a higher amount of sugar in them, and thus the yeast will produce a higher volume of alcohol. If the alcohol level rises above 16-18% ABV, the yeast will probably die, causing the fermentation to be stuck. - 15432
