Alcoholic Fermentation

Alcoholic Fermentation - Types

Industrial Fermentation

First, let’s talk about industrial fermentation. This process has evolved to improve the chemical efficiency of the process and obtain larger quantities of ethanol. How is this achieved? With continuous alcoholic fermentation in controlled environments. In this way, we can process alcoholic beverages such as wine and beer at an appropriate pace to offer them to the market.

But that’s not all! There is also a research path to improve industrial processes by improving yeast strains. For example, the Zymomonas Mobilis yeast strain offers advantages in continuous fermentation processes by allowing a higher yeast density during production.

Continuous fermentation began to be patented in the 1950s and since then, the alcoholic beverage industry has experienced appreciable growth. A key feature of industrial ethyl fermentation is the appropriate selection of yeasts to increase production yield.

So, how is industrial fermentation carried out? Essentially, this process occurs in a container called a fermenter or bioreactor, where certain substrates in the culture medium are transformed into metabolites and biomass through microbial reaction. These containers are hermetic and allow the removal of the resulting carbon dioxide. During the process, microorganisms increase in concentration during the reaction, while the medium changes its chemical properties and new products are formed as a result of anabolic reactions.

Natural Fermentations

Natural fermentations are a process that occurs spontaneously in nature when there is sugar and lack of oxygen. Did you know that some fruits such as melon and coconut can also undergo an anaerobic ripening process that gives them an alcohol smell? Interesting, isn’t it?!

In winemaking, a key process is the tumultuous fermentation, which occurs in stainless steel mother tanks with grapes in the initial phase. This leads to the appearance of the first traces of ethanol. Additionally, there is another very common type of natural fermentation in fruits called Carbonic Maceration, which is used in some vinification processes of certain wines. Beware, as this fermentation can cause intoxication to insects that feed on ripe fruits, such as bees! So, one must be careful!

Specific Fermentations

There are fermentations that are specific and are manipulated by humans in order to obtain ethanol in beverages. They mainly use sugars found in fruits, cereals, and milk. The production of these drinks is usually done locally since it depends on the availability of these products.

For example, in Mediterranean countries, grapes are frequent, and therefore, wine fermentation is as well. This same pattern can be followed using other materials such as rice in Asia or corn in Latin America. In this way, the tradition of fermentation processes has been associated with different social groups and ethnicities.

Wine Fermentation

Wine making is a very old and well-known process that involves the fermentation of grapes with the help of yeast. These microorganisms are naturally found on the skin of grapes and are responsible for transforming grape sugar into alcohol. To ensure that fermentation takes place properly, the must (grape juice) is sterilized with sulfur dioxide before the process.

Wine fermentation can last up to two weeks and occurs in special containers called fermenters. Once the “primary” fermentation has finished, the young wine is racked to other containers where secondary fermentation occurs. White wines ferment at lower temperatures than reds, and in some cases, more sugar can be added to accelerate the process. The final result is a beverage with a minimum alcohol content of 9% by volume.

• In addition to alcoholic fermentation, there is also malolactic fermentation that occurs after alcoholic fermentation. In this stage, bacteria transform the malic acid in the must into lactic acid, which reduces the acidity of the wine and gives it a smoother, rounder texture.

• The fermentation of wine can be influenced by a variety of factors, such as temperature, oxygen level, acidity, and the yeast strain used. These factors can affect the flavor, aroma, and structure of the wine.

• The aging process of wine can also affect its flavor and aroma. Young wine may have a fruity and fresh taste, while aged wine may have a more complex flavor and often contains notes of spice, leather, and tobacco.

• The quality of wine can also be influenced by the type of grape used and the place where it was grown. The term “terroir” refers to the unique characteristics of the soil, climate, and topography of a region that can influence the flavor and aroma of the wine produced there.

• The addition of sugar to the must to increase the alcohol content of the wine (chaptalization) can be controversial, as some believe it can negatively affect the quality of the wine and reduce its authenticity.

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Alcoholic Fermentation – Types