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Alcohol Fermentation

alcohol fermentationAlthough many people consume alcohol on some basis, most of them aren’t actually aware of the process chain leading from grain on the fields to the beer on their tables. Here is a depiction of the process of alcohol fermentation, one of man’s oldest, and most successful methods to create alcoholic beverages – but not only.

What Alcohol Fermentation Is

Fermentation is generally the process of deriving energy from the oxidation of organic compounds. In simpler terms, carbohydrates, typically sugar, are conversed into an acid or alcohol by oxidizing them, essentially, moving energy away from them and into other compounds. Ethanol fermentation is specifically the process of converting sugars such as glucose, fructose and sucrose into energy, producing in this process ethanol and carbon dioxide as metabolic waste products. The active material performing the conversation is yeast.


Fermentation is associated at the earliest with the making of alcoholic beverages, some 9000 years ago (7000 BCE), in the Middle East region. This fermentation of alcohol precedes the fermentation of foods such as milk and some vegetables, which happened both China and in the Middle East, and is generally thought to be the first instance of applied fermentation known to man.

alcohol stillChemical Process

As an example, we will look at the chemical process of fermentation of glucose, although this process can be generalized to other types of sugar. The chemical formula of glucose is C6H12O6, meaning it contains six carbon atoms, 12 hydrogen and 6 oxygen atoms. In the process of fermentation, one unit of glucose is converted into two units of ethanol and two of carbon dioxide with the enzyme mixture which comes from yeast, that catalyzes the fermentation process. The formula is as follows:

C6H12O6 + Zymase → 2C2H5OH + 2CO2

With C2H5OH being ethanol, and CO2 carbon dioxide.

In less scientific terms, yeast is mixed with grains, typically barely, wheat, or rye (in making of beer), or with grapes (in the making of wine), after those had been let to germinate and dry, and been pulped into a mash and mixed with hot water. A certain part of the yeast „eats up“ the sugar present in the mash, the glucose we have described before, and converts it into carbon dioxide and alcohol.

Examples of Different Scales of Production

The process described above is suitable for different levels of production which can be gaged completely differently. Although it’s essentially the same process in all types of production, the execution is typically different depending on the people to consume the end product.

Home Brewing

Home brewing is often a very simplified process involving homebrewing kits, including all the ingredients necessary to create homebrew from beginning to end, thus reducing the cost for the private person. Most kits include grain and hops, while some may include yeast as well. In addiction, a set of instructions usually complements the kit.

Small to Medium-Sized Breweries

Primary fermentation in breweries takes place in large glass or plastic containers, or food grade plastic buckets, almost always sealed. When sealed, the fermenter is stoppered with a fermentation lock which allows the carbon dioxide gas produced to vent (this gas is not needed), meanwhile preventing other gases and particles from entering. During this time, temperatures should be ideally kept at a optimum temperature for the particular yeast type being used. For ale, this temperature is usually 64–75 °F; for lager it is typically much colder, around 50 °F; wine normally starts fermenting around 68 °F, while cider between 59–64 °F.

fermentation processA strong fermentation then takes place, usually starting within twelve hours and continuing over the next few days. During this part, the sugars are consumed by the yeast as described previously, while ethanol and carbon dioxide are produced as byproducts of this process. A layer of sediment appears at the bottom of the fermenter, composed of heavy fats, proteins and inactive yeast.

Often, the brew is moved to a second fermenting vessel after primary fermentation, called a secondary fermenter. This secondary fermentation process is often used by more advanced home brewers to enhance flavor. Although not required, it is generally practiced by many who wish to age or clarify their beer by removing it from the sediment left behind by primary fermentation.

When the fermentation is concluded, the product is typically ‘primed’, or added a small quantity of sugar and then bottled. For most brews, flip top bottles with rubber stoppers, such as Grolsch, are popular. Bottling can also be achieved by using plastic bottles that have already been exposed to pressure (i. e. soda bottles) provided they are properly sanitized. The act of priming briefly reactivates the yeast that remains in the bottle, carbonating the brew. Homebrewed beers and lagers are typically unfiltered.

Wide Scale Industrial Production

Industrial production of alcohol is not completely different from small or medium scale production. Obviously, the process is very similar, but some adjustments are made in order to allow for wider , more efficient production. Typically, different sort of yeasts may be used, including some that are better for the production of heavier beverages, such a turbo yeast. This dried yeast is fortified with micro nutrients that allow it to happily ferment stronger alcohols and continue doing so even in higher temperatures. The result is yeast that is highly alcohol tolerant as well as temperature tolerant and can reward the production with stronger alcohol as well as higher yields for alcohol from weak mashes or musts, which in turn reduces production costs while increasing in strength and quantity when you use tough yeast such as turbo yeast.

Typically, high-quality orientated industry prefers better yeast types, in order to create quality products and unique tastes, whereas brands including mass production of beer use normal yeast.

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