What is Fermentation?

Posted by Paul on 13 July 2011 in Learn | 0 comments

Photo credit: Ian Brown

Consumption of alcohol and strenuous exercise don’t go together, as one usually negates the goals of the other. However, alcohol and exercise share a common biochemical process: fermentation.
Fermentation is a biochemical process that ultimately converts sugar into cellular energy, leaving behind one of several organic byproducts depending on the type of fermentation. Unlike cellular respiration, fermentation is an anaerobic process, meaning it takes place in the absence of oxygen.

From a culinary point of view, the most common type of fermentation is ethanol fermentation. Yeast and some species of bacteria (yeast are actually single-celled fungi) break down sugar to produce cellular energy. The process generates ethanol (aka ethyl alcohol, grain alcohol, drinking alcohol) and CO2 as waste products. This process isn’t as energy efficient as respiration, but it works in the absence of oxygen which has a number of advantages in the microbial world.

Fermentation has a number of uses in the human world as well. Alcohol production is one of the oldest chemical industries in human history. Brewed and distilled alcohol are not just fun to drink. In the absence of a reliable source of fresh water, alcoholic beverages can be a reasonable substitute. Alcohol, being a biochemical waste product, acts as a natural disinfectant and antimicrobial compound. In high enough concentrations, alcohol kills bacteria, viruses, and microbial fungi. This is why wine, beer, and ale played such a prominent role in medieval societies and why rum was once a sailor’s best friend. Drinking alcohol was much less likely to spread disease than pure water. We continue to utilize alcohol’s antiseptic qualities today in the form of alcohol swabs and hand sanitizing gels.

So, what does fermentation have to do with exercise? No, fermentation is not responsible for the odor emanating from your socks or gym bag after a workout. As mentioned earlier, there are different types of fermentation based on the organic byproduct produces. Although people and other multicellular organisms are incapable of ethanol fermentation, our muscles can carry out another type called homolactic fermentation.

When your muscles need more energy than aerobic respiration can provide or available oxygen can support, such as during strenuous exercise or a sudden burst of activity, then can produce energy via anaerobic respiration which is really just fermentation. (Contrary to popular belief, this type of muscular activity does not produce lactic acid and is not related to the burning sensation felt in muscles after exercise.)

Fermentation produces cellular energy without the use of oxygen. Depending on the organism involved – and fermentation always requires some sort of living thing to carry out the complex series of reactions involved – a variety of organic byproducts are produced. So whether you finished off a long jog with a 100 yard sprint or are enjoying a glass of wine at the end of the day, fermentation is involved.