Everything you need to know about the fermentation of tobacco leaves

The making of a cigar is a slow and meticulous process during which tobacco leaves go through different stages of transformation. Among these stages, fermentation plays a crucial role. It is what makes it possible to eliminate impurities contained in the leaves, develop their color, and refine their aromas. In this article, we explain how the tobacco fermentation phase unfolds.

What is the purpose of fermenting tobacco leaves?

Fermentation of tobacco leaves is the stage that comes right after drying. It generally lasts between 30 and 90 days. In reality, we should speak of “fermentations” in the plural. This step actually takes place over two cycles: one cycle that occurs after drying, then another cycle that takes place after sorting and stripping the leaves. Some brands like Cohiba are also famous for carrying out a third fermentation. Performed in barrels, this last one makes it possible to refine the aromas and flavors of the leaves even further and eliminate the last impurities. Because of their fragility, wrapper leaves undergo only one fermentation.

During the first fermentation phase, a large number of impurities contained in the leaves are eliminated, such as proteins and carbohydrates. This process also reduces nicotine content, the amount of tar, and the leaves’ acidity. It is also during this stage that the leaves acquire a more supple structure and develop a uniform color. For its part, the second fermentation phase refines the aromas naturally present in the leaves and eliminates the remaining impurities.

Fermentation is a process that requires close monitoring of temperature. Under-fermentation will indeed produce tobacco with a bitter taste that burns poorly, while fermentation that lasts too long will wear out the leaves and cause them to lose their flavors. Although fermentation methods vary slightly from one manufacturer to another, it is therefore essential to comply with certain manufacturing standards when one wants to obtain quality tobacco.

The first fermentation phase

Once the drying period is over, the leaves are stacked on top of one another to form “gavillas”. These piles are then covered with a fine cloth to encourage air circulation. The little moisture still present in the leaves, combined with the pressure created by their compression, will trigger a spontaneous heating process and lead to fermentation. This rise in temperature helps speed up the breakdown of the microorganisms contained in the leaves, following the same process at work in the composting of fruit and vegetables.

To produce high-quality tobacco, it is essential that the temperature inside the bales does not exceed 35° C. This temperature must therefore be checked regularly. This meticulous process must also be carried out uniformly. Once the temperature at the center of the gavillas has been reached, they are dismantled and rebuilt according to a precise pattern. The leaves at the center are moved to the top, those at the top are moved to the bottom, and the leaves at the bottom are brought back to the center. This movement is repeated until all the leaves have been treated evenly.

It should be noted that not all tobacco leaves are fermented for the same length of time. For example, the leaves at the top of the plants must undergo a longer fermentation because of their thickness and higher oil content. On average, the first fermentation phase lasts about thirty days.

The sorting and stemming phase

Before the second fermentation, the binder and filler leaves go through a sorting and stemming phase. During this stage, the leaves are first humidified to make them more pliable. They are then sent to a stemming center, called a “despalillo”, to have their central vein removed. The wrapper leaves, by contrast, are sprayed with pure water to prevent stains, then set aside.

Once this step is complete, the leaves are sorted according to their use, size, texture, color, and quality. Only the best leaves are kept to make the filler. They are then gathered into bales before undergoing a second fermentation phase.

The second fermentation

During the second fermentation, the binder and filler leaves are assembled into “burros” that can weigh up to 2,000 kg. Bales that are too small could lead to mold formation, while bales that are too large would not retain enough moisture for fermentation. This stage lasts up to 60 days, and the temperature is carefully monitored so that it never exceeds 42°C.

If the temperature becomes too high, the bales are taken apart to allow the leaves to cool. It is estimated that it takes about four people and 4 hours of work to break down and reassemble a bale. When they are put back together, the position of the leaves is changed in order to achieve a perfectly even fermentation. As during the first fermentation, the thicker leaves undergo a longer fermentation than the thinner leaves. This stage ends when the temperature stabilizes.

What happens after fermentation?

Once the second fermentation is complete, the tobacco leaves are sorted once again according to quality, then placed on shelves for several days to let them air out. They are then wrapped in burlap sacks and sent to storage centers.

Each lot is labeled and includes various details such as the harvest year, the type of leaves (seco, ligero, volado), their size, the name of the sorting center, and the date when the aging process began. This aging phase can last from 6 months to several years. In general, the most aromatic leaves are those that undergo the longest aging. Once the leaves have finished aging, they are sent to the manufacturing factory, where they will be rolled by the torcedors to form a cigar.