An Overview of Alcohol and Fermentation

Fermentation is a process used during the production of alcoholic beverages and many types of foods. Technically, fermentation is the process that a micro-organism uses to gain energy from sugar in the absence of oxygen. This is exactly what the yeast used in alcohol production is doing, at least in the most common types of beverage fermentation. The general idea is that yeast will metabolize sugar that is naturally present in a substance or added to a substance, and produce alcohol and often acids. This alcohol byproduct of yeast fermentation is what gives an alcoholic drink its stoutness; this sort of fermentation is known as ethanol fermentation.

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.

The bottle’s neck was heavily serpentine, and this meant that though the broth was exposed to air, it shouldn’t ferment as it would in a normal bottle. This was Pasteur’s hypothesis, and is exactly what occurred. This experiment showed that some catalyst was required other than air and a substrate for fermentation to occur.

An unusual method used to flavor beers is used by Mountain Brewing Company, a beer-making outfit in Arizona. They use a wort that includes roasted chili peppers, which have a distinctive taste that remains unchanged throughout the fermentation process. Some American malt liquors actually use dextrose as a cheap adjunct, coupled with specific enzymes, to cut the costs associated with fermentation and brewing.

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