By Tad Gage
There has always been a considerable amount of discussion, and information, about aging cigar leaf once it’s picked,
the value of aging tobacco for years in tercios (burlap or palm leaf wrapped blocks before leaves are turned into cigars) and the merits of aging cigars once they’re constructed. You often see discussions of vintage leaf and years of aging and maturing.

However, between the initial air curing of the tobacco leaves and their long, slow aging in bales as they await their final destination as cigars is a violent and not terribly romantic period in a cigar leaf’s journey. It is a decidedly nasty process that may also be the single most important stage in creating a good cigar –  Fermentation. Imagine a barn redolent with the stench of decaying vegetation. Consider the 12 labors of Hercules as punishment from the Greek gods for his destructive raging after his wife’s death. One of those tasks was to clean the foul-smelling Stygian stables in one day. While Hercules handily solved the problem by diverting a river to wash out the stables, there’s no such luck with a tobacco fermentation warehouse.

So why is the process of fermenting, or sweating, tobacco leaves one of those things seldom regaled in discussions of cigar leaf? Well, first, because it is not particularly pleasant or romantic. A darkened warehouse with piles of tobacco doesn’t present the best of photo opportunities, either. Finally, there is a great deal of finesse and proprietary techniques involved, and manufacturers don’t necessarily want to expound in much detail about their particular methods. However, the basics of sweating tobacco are pretty much the same. I’ve always thought the process fascinating, and the transformation the tobacco undergoes during sweating contributes to my appreciation of a great final product.

If you have ever smoked or smelled the classic "El Ropo" cigar, you’ll know that one of the predominant characteristics is a harsh, ammoniated taste and stench. While the uninitiated may recoil at the smell of any cigar, we know that the scent and taste of a great cigar is smooth, with hints of sweetness and nuanced flavor running the gamut from berries and spices to leather. It is the fermentation, or lack of it in El Ropo’s case, that makes this all possible.

First and foremost, you have to start with great leaf. Poor quality cigar leaf, no matter how well aged or perfectly fermented, will never yield a fine product. This is where cigar leaf culture is much like making great wines: the soil, climate, choice of leaf, location of the leaf on the plant and the time of harvest completely controls the quality and character of the leaf.


With wines, you can nibble on a grape and it will probably be enjoyable. If you’re an expert, you probably have a good chance at tasting how this grape will need to be processed and aged. But, you cannot nibble on a perfectly ripe, green tobacco leaf and come up with anything but a taste only a bug could love. In this way, tobacco is more like coffee; it’s hard to tell much from the freshly picked leaf or berry, or even the dried product. Only when the leaf is cured, fermented and aged, or the coffee "bean" roasted and brewed, can you really know what you have.

Air curing the tobacco in the fields can offer the first hints of the ultimate product when an expert grower singes the leaf, and savors the aroma. But, that’s just a hint, and it’s in the sweating of the leaf that the heavy lifting occurs. Initiating the time-consuming, labor-intensive process of fermentation is a leap of faith, but it’s an investment that manufacturers must make before they can evaluate the ultimate quality of the leaf.

The first step after picking perfectly mature tobacco is to cure it. Generally, this is a 45 to 60 day process with the leaf hung in tobacco barns, using only natural air movement to slowly dry the leaf. Most premium cigar leaf is air cured in this way. Heat curing is a quicker alternative, but because it’s a faster, it tends to arrest the development of oils and flavors, and is rarely used in the production of fine cigars.

Without the fermentation process, plant sugars would convert to starch, much in the same way that an ear of corn is less sweet a week after picking than fresh off the plant. Fermentation sort of reverses this process, causing plant starches to convert to sugars. It also makes the significant contribution of driving unwanted chemicals and bitter resins from the leaf using the heat of the composting process. And while not a romantic term, sweating tobacco is essentially composting.

Once the leaves are air cured in tobacco barns, they’re sorted by size and type and carefully piled in bulks. Leaves are layered on the floor of a fermentation warehouse in two- to four-foot piles. The process is overseen by a skilled zafador, who has many years of experience in arranging the piles "just so." Frequently, PVC tubing is layered into the growing piles at strategic intervals to help manage the flow of air into the sweat and the heat being released. Any of you who are gardeners and maintain a compost pile know that the vegetation at the bottom will decay more quickly and generate more heat from decomposition than the top layer. In a standard garden drum-style composter, you just crank it around once in awhile to promote even composting. Of course, such a haphazard practice would spell disaster for tobacco leaves, which must be kept whole and intact.

So finally, you have room filled with mounds of cigar leaf and the magic begins. The leaves begin to break down under heat and pressure. They don’t crumble to dust, of course, but certain elements start to be released. Ammonia is released, causing the characteristic stink even in the well-ventilated fermenting warehouse. If the ammonia isn’t completely exorcised, you will have tobacco that are only good for making that "El Ropo" we mentioned earlier. Sweats can reach 115 to 140 degrees Fahrenheit. Frequently, sweats are covered with burlap or palm leaves to help manage moisture and heat levels.

Even with tubes to control heat levels and vent exuded moisture, sap, resins, and unwanted chemicals present in nearly all plant matter, the bulked tobacco requires regular rotation to ensure even fermentation of the leaves. Top leaves may be moved to the middle or bottom of the pile, bottom leaves to the top, while middle leaves may get moved to the top. This is strikingly similar to how Scotch or Bourbon whiskey makers will rotate barrels from upper to lower floors in their aging warehouses to ensure the booze-filled barrels receive equal exposure to heat and air movement.

It’s not uncommon in this initial sweat to turn a pile ten times or more to get an even fermentation throughout the pile and from leaf-to-leaf. The process of managing tobacco bulks requires tremendous skill to create a balanced fermentation. In tobacco, nicotine is reduced during the sweating process, and as the leaves lose their final traces of chlorophyll, their color becomes more uniform and remnant green blotches disappear.

Sweats usually last from two to four months. Smaller bulks will generate less heat and decompose more slowly. During this period, some of the "trade secret" aspects of fermentation come into play. Some makers claim longer, slower sweating or more frequent turning contribute to their tobacco’s mellowness. Others sweat the tobacco more quickly, with the same goal of a perfect end-product. Regardless of the method, the internal temperature of the bulk starts high and declines with time as unwanted compounds are consumed.

Once the overall bulk temperature drops below 90 degrees Fahrenheit, the initial sweat is nearly finished. The zafador (bulk master) must make a skilled decision about when enough is enough. Essential oils, moisture and just the right amount of nicotine may be lost if the bulk is allowed to continue too long.

The limp leaves are removed from the sweat and stripped of their central vein, splitting the leaves in half. The stems still contain compounds that will enter the leaf if allowed to remain. It’s a real judgment call to determine when the stem has contributed as much as it should. The leaves are then bulked for a second, gentler sweat. These bulks are smaller and exert just enough pressure to flatten the leaves and create pressure sufficient to press out moisture, which sinks back into the leaves. This creates increased complexity.

The process is similar to how Perique pipe tobacco is processed. Burley leaves are fermented in barrels under pressure, with each successive sweat drawing out moisture and oils, which then sink back into the tobacco. The final result is a rich, black, spicy tobacco that bears no resemblance to the tan tobacco leaves at the start of the process.

The second fermentation of cigar leaf is much less dramatic. Temperatures don’t exceed 85 degrees Fahrenheit. Oils and moisture become evenly distributed through the stripped leaves, the final starches convert to sugars, and any last traces of ammonia dissipate. This second sweat can take weeks. When finished, the leaf is ready for baling and slow aging that can last for many years as the tobacco awaits its final flowering as a finished cigar.

Fermentation is a time-consuming, costly, labor-intensive process. It takes longer to properly sweat tobacco than it does for the tobacco plant to grow from seedling to maturity. It may now be clearer why this process is tempting to rush when creating cheaper cigars, but the downside of rushing this process is evident when you taste residual plant chemicals, resins and starches instead of sugars. Careful and skillful fermentation is one of the main reasons your premium cigar is as much a work of art as any fine wine or spirit.

[Editor’s note: Tad learned about tobacco fermentation first-hand while visiting different cigar manufacturers in various locales such as The Dominican Republic. What is quite interesting is that fermentation is managed somewhat uniquely by each cigar maker, and even more differently in Cuba. I phoned Jorge Armenteros, the creator of Tobacconist University to ask why TU’s information on fermentation was different than Tad’s. He explained that he learned the fermentation methods first-hand as well, but while visiting Cuba! He also informed me that methods continue to evolve. The same manufacturer may even have several different procedures, while they continue to experiment with new fermentation recipes.]
First and last photos courtesy of Tobacconist University. Used with permission.

Read more about curing and fermentation at Tobacconist University at these links:
Curing & Fermentation Pg 1
Curing & Fermentation Pg 2
Curing & Fermentation Pg 3
Curing & Fermentation Pg 4
Curing & Fermentation Pg 5
Curing & Fermentation Pg 6
Curing & Fermentation Pg 7


Tad GageTad Gage is the author of the best selling Penguin Books "The Complete Idiot’s Guide to Cigars," in its second edition. The book has sold over 40,000 copies worldwide, in three languages, and is available in stores and online distributors. Tad has made cigar connoisseurship accessible to beginners and veteran cigar smokes alike. He is delighted to answer questions through Just comment below.


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