Fermentation – the act of releasing ammonia from tobacco leaves using moisture and extreme temperatures.

To ferment tobacco, the leaves are stacked 4 to 6 feet high in pilones (piles), moistened, and then allowed to rise in temperature. Temperature is the most important part of this process, and may reach 140 degrees. Temperature is constantly observed and regulated, while the leaves are re-stacked to ensure even distribution until fermentation comes to an end naturally. During the fermentation process, the leaves emit ammonia and other compounds like sugar and sap, which come to the surface and create rich, mellow, and smooth flavors. The leaves also become significantly darker in color.

Fermentation explains how a natural leaf becomes maduro, naturally. By introducing the leaves to more or longer fermentation processes, a maker can create a darker and richer leaf. Some manufacturers will restack their pilones as many as 10-12 times.

The extent of the fermentation process is solely based on the cigar maker's preference for each particular type of leaf. From start to finish, this process could take as little as a month, or last up to 3 years, sometimes longer! There is no set rule. But, rest assured, most of today's top manufacturers properly ferment their tobacco leaves to ensure an optimum cigar experience.