Cuban vs. \"the rest\" - chemical analysis?


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We've all seen the plethora of questions about "what makes Cuban tobacco special?" What I've never seen, however, is something like a chemical analysis of tobacco from different countries, regions, etc.. I guess to keep it short - have I missed something?

If it hasn't been done; why not? I'm sure there is plenty of money to fund such a venture . . .

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» We've all seen the plethora of questions about "what makes Cuban tobacco

» special?" What I've never seen, however, is something like a chemical

» analysis of tobacco from different countries, regions, etc.. I guess to

» keep it short - have I missed something?

I can't recall reading a specific scientific report on the hows and whys, but we have had general

discussions on the topic.

In general I feel (and I don't think I'm alone) that it's not just the seeds used. It's the soil, the climate,

the micro climate within and between regions that give tobacco it's unique characteristics.

Add to that how the tobacco is grown and processed as well.

I think the wine analogy works well here - why is pinot noir from Burgundy as different as it

it from pinot from elsewhere?

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» We've all seen the plethora of questions about "what makes Cuban tobacco

» special?" What I've never seen, however, is something like a chemical

» analysis of tobacco from different countries, regions, etc.. I guess to

» keep it short - have I missed something?

»

» If it hasn't been done; why not? I'm sure there is plenty of money to fund

» such a venture . . .

I saw an article about this a while back:

http://www.cubanet.org/CNews/y01/apr01/06e8.htm

US Customs also appears to do some sort of testing. Lew Rothman used the results of one of these tests as a selling point in a recent catalog. Here is the related story:

https://www.cigarcyclopedia.com/webapp/content/view/1031/58/

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» We've all seen the plethora of questions about "what makes Cuban tobacco

» special?" What I've never seen, however, is something like a chemical

» analysis of tobacco from different countries, regions, etc.. I guess to

» keep it short - have I missed something?

»

» If it hasn't been done; why not? I'm sure there is plenty of money to fund

» such a venture . . .

Here you go.

This is an article that seeks to bring the technical world of cigars and tobacco to the average smoker. As enthusiasts and aficionados, we live in the sensual world. The language we use when talking about our hobby is descriptive, colorful and can even approach the poetic. But on the other side of the leaf, there are people to whom tobacco is a job. These people are the makers of tobacco products, scientists interested in tobacco husbandry and members of government agencies charged with preserving tobacco products tax income. These people are intensely concerned with aspects of tobacco that we might never become aware of even after a lifetime of smoking. Still, their work can often indirectly affect our enjoyment of cigars. So, pull up a chair, pour a tall one, and spark up your favorite stick and join me as I guide you through the mysterious underworld and backwaters of tobacco science.

The article up for analysis is one that some of you might have heard about in the popular press. It concerns an issue that is near and dear to us; the authentication of Cuban cigars. However, while we're concerned with insuring that the cigars we purchase are the real deal, there are others to whom the issue of authentication is much more weighty. In this case, it is the Canada Customs and Revenue Agency and the concern is with tax revenues. For those who have traveled to the Great White North and purchased cigars there as I have, you're well acquainted with the rapacious taxes on Cuban cigars. It is in the government's interest to insure that every purchase of a Habanos product involves authentic goods imported by Havana House (the authorized distributor of Cuban cigars in Canada) precisely because these taxes are collected.

Original Citation

"Characterization of Cigar Tobaccos by Gas Chromatographic/Mass Spectrometric Analysis of Nonvolatile Organic Acids: Application to the Authentication of Cuban Cigars"

by: Lay-Keow Ng, Michel Hupé, Micheline Vanier, and Dennis Moccia

in: Journal of Agricultural and Food Chemistry, 2001, volume 49, pages 1132-1138

From the introduction:

"Cuban cigars are acknowledged as among the finest in the world. Illegal sales of smuggled or counterfeit Cuban cigars have sprung up in recent years to meet the high demand for the commodity...such activities result in the loss of millions of dollars in national revenues."

Problem statement:

Develop a quick and reliable method to differentiate cigars of Cuban origin from cigars using tobacco from other countries.

Theoretical Basis:

Tobacco contains two signature chemical compounds (nicotine and solanone) in addition to a potpourri of other biochemicals. By turning leaf into cigars this mash of "stuff" undergoes a transformation into a characteristic chemical "profile" that reflects:

1. the genetics of the tobacco plant

2. the agricultural conditions and processes experienced by the plant (soil, fertilization, weather)

3. the processing conditions and history experienced by the tobacco (curing and fermenting techniques)

Why should this work for Cuban cigars?

1. The Cubans tightly control their seed and tobacco strain resources. As one of their largest revenue sources (behind minerals and tourism) and as a result of historical disasters due to Blue Mold, they conduct ongoing research into developing varieties of tobacco with disease resistance and yield in mind. Nobody can just plant seeds and grow leaf. Farmers are given live seedlings by the Station of Tobacco and they are not allowed to let plants go to seed. As a result, the genetics of Cuban tobacco are highly uniform.

2. Much has been said about the contribution of the Cuban climatic conditions and the legendary Vuelta Abajo soil to the quintessential character of the Havana cigar. From the smoker's perspective, this debate has no resolution. However, for the purposes of this analytical technique, this isolation and high degree of control over the husbandry (processes of growing and cultivation) of tobacco provides the consistency that is critical for success.

3. The processing of tobacco, though carried out in relatively primitive conditions, is precisely monitored and well practiced after decades of refinement. Curing, fermenting, and aging are managed with great consistency of technique. This lends yet another dimension of regularity that is essential for this analysis.

The Target:

The authors of this study selected a group of organic acids around which to develop a fingerprint profile. These were compounds such as glyceric and malic acids and bear no relation to nasty inorganic acids like hydrochloric and sulfuric. I won't go into the reasons why this class of chemicals were selected other than to say that the relative amounts of these have been used by other researchers to identify other types of tobacco.

The Technique:

They selected the technique of gas chromatography coupled with mass spectrometry or GC/MS. This is a common and powerful technique that can do two things critical to solving this particular challenge.

1. GC is able to separate the various organic acids in the leaf extract.

2. MS is able to identify those separated components.

In essence, they obtained cigars, disassembled them, ground up the leaves and extracted the target chemicals for analysis and then subjected them to GC/MS for separation and identification.

Materials:

18 different Cuban cigars provided by Havana House

31 different non-Cuban manufactured cigars (10 from Honduras, 6 from the Dominican Republic, 5 each from the U.S. and Nicaragua, 2 from Mexico and 1 each from Brazil, Jamaica, and Aruba)

They fully acknowledged that cigars made in a non-Cuban country could contain tobacco from a number of different national origins and they simply grouped all the NC cigars together as "non-Cuban." While they did separate the wrapper from the filler and the binder, it is unclear whether they tested binder at all or whether they grouped it in with the wrapper or filler. Their results only identified wrapper and filler testing.

The Data Analysis:

I won't go into the details of the GC/MS tests. It would be constructive only to say that this test did in fact yield chemical profiles that were distinctive of Cuban and non-Cuban tobacco. These profiles consisted of eleven chemicals found in all tobaccos but at specific and varying ratios.

By using the statistical data reduction technique of principal components analysis (PCA) the investigators were able to identify two aspects of these profiles which accounted for an astonishing 98% of the explanatory power of the analytical technique. This is an incredibly high number which means that the ability and reliability of this test to differentiate Cuban and non-Cuban tobacco is very robust.

The Results:

Filler tobaccos - With the exception of a single specimen, ALL the Cuban cigars clustered in one group completely apart from the cluster of non-Cubans. I cannot reproduce the PCA chart without permission but it was very clear that Cuban and non-Cuban filler tobaccos were clearly and distinctly separate groupings.

Wrapper tobaccos - Unlike the stunning results of the filler tests, the wrapper samples showed no discernible natural grouping. In other words, Cuban and non-Cuban wrapper tobaccos were indistinguishable from each other.

Commentary:

1. It appears that these researchers have indeed developed a quick and reliable analytical method that is capable of distinguishing Cuban from non-Cuban tobacco and thus presumably authentic from counterfeit Cuban cigars. While this may prove effective in detecting counterfeits of non-Cuban origin, the same factors that render the Cuban fingerprint so reliable may make the detection of Cuban-made counterfeits impossible with this method.

2. Why did the test work wonderfully with the filler tobaccos yet fail with the wrapper tobacco? Although the authors made no mention of this, as smokers, we are well acquainted with the sales tagline "Cuban seed" tobacco. I think that if any significant number of these wrappers were made from Cuban-seed tobacco, then they might well carry a genetic component that is very similar to Cuban-grown leaf. If this is the case, then one of the three factors identified above as contributing to the development of a characteristic fingerprint profile is wiped out.

Additionally, since most references state that (aside from maduro) natural wrappers are always processed at gentler temperatures than filler and binder tobaccos, this means that there may be a lower degree of transformation of chemical components as a result of the processing. This would mean the specific contribution of a second fingerprint factor would be reduced.

These two issues may well have contributed to the failure of this technique with wrappers. I'm presuming that the investigators were not avid cigar smokers or students of tobacco science. As a result, they would not be aware of these mitigating issues.

3. As far as any practical results of this work, for us, there is none. This is not a test that we could do in our kitchens. And, since there is an embargo of Cuban goods, this is not an issue for those U.S. organizations concerned with tax revenue. However, the BATF Tobacco Tax and Trade Bureau is presently conducting very similar tests on tobacco discrimination and could well adopt this method if and when Cuban cigars become available and taxable.

Feel free to post questions or requests for clarification.

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If you look at the actual JAFC paper, you will find a couple of things:

1. their sample size is very limited. To accurately use PCA analysis for categorization of data, you need a huge sample size for validity. Sure, you can run the analysis with a few dozen data points, but the validity suffers. They need to analyse hundreds of samples from different years, different marcas, different NC origins, etc. They did not do this.

2. their PCA analysis shows some overlap between C and NC cigars. Even one overlapping data point raises the question of data validity.

To properly run the analysis, they need to either run an analysis of volatiles form the cigars or from smoke produced from the cigars. They need to do this because the difference we find in Cuban cigars is one of taste primarily.

A lot of work has been done using electonic noses ... look for a paper on this very soon. They can categorize samples based on volatile compounds (aromas) that a machine sensor detects. I have used these for many publications and found that they work surprisingly well. Same caveat applies regarding sample number.

It would be relatively simple to use solid phase microextraction with gas chromatography mass spectrometry to analyse the cigars. I haven't done this although we use SPMEGCMS routinely because ... well ... where I live Cuban cigars are illegal. However, if the US or canadian customs officials want to send me cigars for analysis I would happily examine them using SPMEGCMS and electronic nose to see if there are identifiable differences between NC and C cigars.

As it is, that analysis of organic acids has been ballyhooed far beyond its ability to reliably distinguish C and NC cigars. I would have recommended rejection or major revision if that came across my desk for review (and I review a lot pf manuscripts for JAFC).

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For the non-scientists out there, "validity" here has two connotations.

First, with respect to a measurement, (internal) validity means that you are measuring what you are intending to measure. So for example, if you wish to measure relative humidity, a hygrometer would give you a readout that corresponds to the condition of interest: humidity. As the humidity varies, correspondingly does the hygrometer reading vary. A thermometer would provide an invalid measure of humidity...but a valid measure of temperature.

Second, with respect to whether the measurement is of value in general use, (external) validity means that the results you get by placing the hygro in your humidor will reflect the humidity as it would if it were in one of my coolers. If both of our storage chambers were known to be at 65% RH, then the hygro should read 65% in both.

Wilkey

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I use this example for data validity.

Lets say aliens from Mars come to the US and want to study humans. They are curious about the differences between men and women since they are hermaphrodites. So they go to the sports arena here at Virginia Tech some Friday evening and measure the heights of 10 women and 10 men.

They conclude that women are taller than men.

Their height analysis was not the problem, they used lasers and measured height to within 0.001". The problem was their data set ... they selected women from the basketball team and men from the wrestling team.

Their analysis was accurate but their data set was not a valid representation of the population of women and men.

When selecting samples for analysis, you need to make sure you have no bias in the selection of samples used to represent populations. The samples of cigars in that Canadian study were not described in enough detail for us to know is there was bias or not. For example, they could have only selected Dominican cigars and they might be particularly different from Cuban cigars compared to Nic, Honduran and others. We just don't know.

So it is impossible to use their study as is as a means of conclusively differentiating cigars. As well, there are significant year to year variations in cigar composition related to growing conditions, strains of tobacco used, etc., and this was not discussed in that paper at all. What about Connecticut or Ecuadorian wrappers? How would that affect results?

Now, maybe they did a much better job of the analysis than was reported in the study ... but I doubt it based on how poorly they characterized their samples and how critical this to the relevance of the work. As well, as I mentioned earlier, there is overlap in their PCA analysis. So at least one of their NC or C samples was in the wrong cluster, making CONCLUSIVE differentiation impossible.

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» Wilkey,

»

» Is the article worth $25 from the ACS? I'm actually interested in the

» quantative difference in the multiple organic acids between island and

» non-island cigars

Since it is one of the very few published works on cigar identification, on that basis, it is. If you can't get a copy otherwise, send me an email here and I will send it to you.

Wilkey

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