Cigar Chemistry: Know Your Carotenoids

Of the thousands of chemical elements that compose a typical tobacco leaf there are a few that take primary responsibility for the taste and aroma of your smoldering stogie. Some of the more important elements have been identified as members of the carotenoid family.  

Carotenoids

Carotenoids are the pigments which give many vegetables and flowers their color. The obvious example is that belicoso-shaped delicacy known as the carrot, from which the word carotenoid derives. Carotenoids give that root its orange color. In other cases the carotenoid content is masked by green chlorophylls, but as the fruit ripens and the chlorophyll content decreases, the colorful carotenoids emerge. This is what happens when a green tomato turns red on the vine.

The process of ripening is really just the early stages of decay — the constituent elements of the fruit, or in this case the leaf, are breaking down and releasing new and more organoleptically interesting compounds. Carotenoids are highly sensitive to oxygen, light, and temperature, and all of these things are carefully controlled by the tobacco grower as the crop is grown, harvested, and particularly during the curing and fermenting stages.

The major carotenoid pigments in tobacco are lutein, beta-carotene, moxanthin and violaxanthin. As these carotenoids break down via oxidation, aromatic derivatives are formed which are crucial and distinctive to the crop. For the sake of example, we can take one of these pigments, lutein, and look at some of its derivatives.

Lutein

Lutein is found in leafy green vegetables, most prominently in spinach and kale.  (And yes, tobacco too.) It is important nutritionally, but for our purposes here we are most interested in what happens when it degrades. Lutein breaks down during the air-curing process to several ionones and their derivatives, such as Beta Damascenone and Megastigmatrienones, two of the carotenoid derivatives which are most responsible for the smell of tobacco.

Beta Damascenone

Beta Damascenone is one of the rose ketones and is considered to be the marker for quality rose oil, even though it is present in extremely small quantities. For whatever reason, the human nose is very sensitive to this smell and very little is needed to detect it. Interestingly, it is found in beer, and is responsible for some of the floral notes in red wine (especially merlot.) In addition to its floral nature, beta damascenone is also associated with the smell of baked apples. It is not present in fresh apples, only baked. Other descriptors:

  • honey
  • plum
  • tobacco
  • blackcurrant

Closely related to the damascenenones (and damascones) are the ionones; in fact, they’re all part of the rose ketone group. Ionones are present in almost every type of perfume, and are almost always described as woody with strong violet accents.  Both alpha and beta ionones have been identified in cured tobacco leaf.

Megastigmatrienones

Don’t ask me how to pronounce it, but megastigmatrienones is arguably the smell of cured tobacco. Its four isomers have been isolated or synthesized and used in commercial applications to impart or “improve” the smell of tobacco and to cover up other unwanted odors. (It is available commercially as “tobacco cyclohexenone”.) It is sometimes held responsible for the note of tobacco that is often detected in full-bodied red wines. Most frequently the aroma of megastigmatrienones is associated with the following:

  • sweet tobacco
  • dried fruit
  • honey

Other interesting carotenoid derivatives found in cured tobacco are theaspirone, an ingredient in black tea and a component of tea essential oil, and beta-cyclocitral, which is described as green, grassy or hay-like.

Conclusion

Many cigar enthusiasts have detected flavors like these at one point or another. Floral, honey and tea-like notes I find most often in milder cigars, usually with shade wrappers.  And while these are just a few of the elements from only one group of the many compounds that contribute to the flavor and aroma of cigar tobacco, I hope it shows that notes of tea or grass or violet are not out of the range of possibility for some experienced cigar enthusiasts.

So if you find yourself musing over the soft wood and floral notes of that ’02 Choix Supreme and suddenly detect a hint of honey, consider yourself fortunate… not crazy.

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8 thoughts on “Cigar Chemistry: Know Your Carotenoids

  1. That is one interesting article, thanks for sharing! I would love to learn more about the Chemistry of the leaf and would appreciate it if you may be able to point me in the right direction.

    • Most of the information in this series of articles comes from a book called Tobacco: Production, Chemistry and Technology, with some other bits and pieces picked off the web. The fields of food science and oenology are closely related to this matter, so looking into those has been helpful as well. Lots to learn and ponder!

  2. very cool. I dig that you’ve been putting some educational shit up here. Makes me feel smarter haha.

    Love the site. Nice work.

  3. Thank you very much for this article. I may possibly be on the same track as you. In particular I often find myself asking questions about cigar storage and traditional protocol when it comes to aging cigars. The obvious goal being to obtain an aged cigar whose flavors reflect the degradation of tobacco, inline with our own personal preferences. Wouldn’t that be something?

    I like x, y and z flavors in a particular cigar.

    Well, in order to maximize the procurement of a, b and c chemicals, you will most likely need to store that particular cigar at _blank_ temp for _blank_ time.

    In the obscenely complex matrix that only a studied and experienced chemist/cigar smoker/botanist could decipher, one would be able to best obtain suitable aging techniques. Unfortunately most, if not all aficionados are lacking in one or more areas of expertise.

    I think you are headed in the right direction and I hope that you continue to delve deeper with your informative articles & refreshing approach.

  4. Very interesting stuff. I’m going to have to look for that book. Glad I found this today, I came across several comments earlier talking about how crazy cigar reviewers are for describing a cigar’s flavor the way they do. Now I can point those tobacco-flavor Luddites to this post and say, “hey, it’s science.”

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