Fermentation is used in the brewing of beer to give beer its foaminess and also to make it alcoholic. It is a very precise process, and different beers will go through different styles of fermentation. Generally, styles of fermenting beer can be divided into two broad types based on the two major kinds of yeast that are used in brewing: top-fermenting yeast and bottom-fermenting yeast. Ale is fermented with top-fermenting yeasts and is brewed at a higher temperature.
These beers were traditionally produced in Great Britain, but are now produced all over the world. The yeast used in lagers is bottom-fermenting yeast, and brewed at lower temperatures. Lagers were mostly made in central Europe before spreading to the rest of the world. Steam beer, which originated in the 1800s in California and is also called California Common Beer, is brewed with bottom-fermenting yeasts, like a lager, but brewed at higher temperatures, like ale. Porter beers and stout beers can be made with a variety of different fermentation styles, as there are many different styles of porters with many different kinds of ingredients, such as oatmeal, wheat, or even oysters.
Usually what occurs when yeast are exposed to oxygen during fermentation is that they continue the anaerobic fermentation somewhat but also perform a small amount of aerobic respiration. The byproducts of this aerobic respiration are usually not as palatable to people, with acetic acid, or vinegar, numbering among those byproducts. Another inhibitor to the fermentation process other than oxygen is too much alcohol in the substance that is being fermented. If the yeast are allowed to produce so much alcohol that the substance being fermented has greater than 16-18% alcohol by volume, the fermentation runs the risk of becoming stuck.
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.
This experiment dealt the final blow to the theory of spontaneous generation, and led to the discovery of enzymes, which are the mechanisms used by living things to digest matter. In fact, Pasteur's work in this field evolved into a science of its own, called zymology. Today, it is called microbiology, and is the result of many modern advances in food spoilage prevention, not to mention a major catalyst in the evolution of the modern medical field.
These beers were traditionally produced in Great Britain, but are now produced all over the world. The yeast used in lagers is bottom-fermenting yeast, and brewed at lower temperatures. Lagers were mostly made in central Europe before spreading to the rest of the world. Steam beer, which originated in the 1800s in California and is also called California Common Beer, is brewed with bottom-fermenting yeasts, like a lager, but brewed at higher temperatures, like ale. Porter beers and stout beers can be made with a variety of different fermentation styles, as there are many different styles of porters with many different kinds of ingredients, such as oatmeal, wheat, or even oysters.
Usually what occurs when yeast are exposed to oxygen during fermentation is that they continue the anaerobic fermentation somewhat but also perform a small amount of aerobic respiration. The byproducts of this aerobic respiration are usually not as palatable to people, with acetic acid, or vinegar, numbering among those byproducts. Another inhibitor to the fermentation process other than oxygen is too much alcohol in the substance that is being fermented. If the yeast are allowed to produce so much alcohol that the substance being fermented has greater than 16-18% alcohol by volume, the fermentation runs the risk of becoming stuck.
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.
This experiment dealt the final blow to the theory of spontaneous generation, and led to the discovery of enzymes, which are the mechanisms used by living things to digest matter. In fact, Pasteur's work in this field evolved into a science of its own, called zymology. Today, it is called microbiology, and is the result of many modern advances in food spoilage prevention, not to mention a major catalyst in the evolution of the modern medical field.
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