Overheard behind us during Barrie’s Talk: “That’s only Listerine”

not exactly, but thymol is an active ingredient in Listerine

imageLast evening at the Cathedral of St. John the Baptist in Savannah, Georgia, Barrie Schwortz (pictured here as he appeared in 1978 with Secondo Pia’s camera from 1898) gave an outstanding talk  on the Shroud of Turin and the work of STURP.  See the TEDx Talk (link in the upper right hand corner) to get a much shorter example of one of Barrie’s presentations. Barrie went on for two hours. My wife and I were totally captivated every minute of those two hours. Barrie knows his stuff. Yes! But he is funny, as well, and we laughed the whole evening. (Thank you Barrie, for mentioning the blog and the discussions we are having about some of the subjects you discussed.)

Towards the end of his talk, Barrie was explaining why should be cautious about a new round of carbon dating at this time. There are some concerns that first need to be addressed. One was the possible effect of thymol on the shroud. Thymol was used to sterilize the shroud’s wood lined reliquary after cutting samples from the cloth. Ray Rogers, in his book, “A Chemist’s Perspective On The Shroud of Turin,” writes:

The custodians had allowed a small sample to be cut from the Shroud for textile analysis in 1973. Without consulting any of the scientists who had studied the cloth in 1978, the custodians allowed a much larger sample to be cut for radiocarbon dating in 1988. The date was reported as AD 1260-1390. At the time the cloth was sampled, the reliquary was treated with thymol, a phenolic compound used to sterilize materials. Thymol reacts with cellulose (linen), and the cloth’s composition has undoubtedly changed.

Rogers, many pages later, goes on to say:

. . . They sterilized the reliquary before the Shroud was replaced in it. They give the times during which bags of thymol were in the reliquary, but there is no way to estimate how much vapor reacted or was adsorbed on the walls of the container Thymol has a high vapor pressure. and it adsorbs strongly to any type of surface. The reliquary was lined with wood. Wood has a cellular structure and composition that favors absorption of materials like phenols. You can think of it as blotting paper for thymol.

Surface areas are routinely measured in science by adsorbing vapors on the materials and measuring amounts (usually called the BET method). A significant amount of thymol could have adsorbed on the wood, and wood has a large cellular surface area. More thymol would have reacted with the cellulose and more reactive hemicelluloses, lignin, and plant gums of the wood. No analyses were done. The amount of thymol left in the reliquary is unknown, but it is critical.

Some thymol would have desorbed and transferred onto the Shroud rather quickly. The desorption would reduce the free thymol concentration, reversing the equilibrium of thymol-wood reactions This would provide more thymol for reactions with the Shroud. Given enough time, reactants keep reacting until they reach their lowest energy state or equilibrium. I can not estimate the composition of the Shroud as it was taken from the reliquary. Apparently the persons involved with the 1988 sampling fiasco did not try.

Thymol is a “phenolic” compound, closely related to carbolic acid (phenol). The use of thymol shows a complete irresponsible ignorance of chemistry. Many superbly qualified chemists live in Europe and the United States, and some of them have had years of experience with the Shroud. They care about the Shroud. Many specialists on carbohydrates would have been happy to consult free of charge. Why were none asked about the long-term effects of thymol on cellulose (linen)? On iron compounds?

Thymol is also called “thyme camphor.” It is obtained by steam distillation of different species of plants of the genus Thymus or Ajowan. All of its carbon is modern carbon. Each modern thymol molecule that is grafted onto the linen will reduce the apparent age of the cloth by some amount. A significant amount of reaction will totally destroy the option for making accurate radiocarbon age determinations on the cloth. . . .

I have heard some say the Thymol effect might be only a few years. I’ve heard others say that we have no idea what the effect might be. Might be is the point.

40 thoughts on “Overheard behind us during Barrie’s Talk: “That’s only Listerine””

  1. There are at least two ways of addressing the possibility of thymol contamination. The first is to buy in some radio-labelled thymol, add it to linen on a sealed container, see how much becomes attached, either physically (by adsorption) or chemically. To check for the latter, one takes the thymol-treated linen through the clean-up procedure used in one’s chosen radiocarbon AMS-dating protocol to see whether or not it detaches.

    What if thymol does attach, and does not detach on clean-up?

    It’s not the end of the world. One coping strategy is to determine what proportion of one’s linen is accountable as carbohydrate. That can be done by acid hydrolysis and glc-mass spectrometry, and measuring all the carbohydrates (glucose, xylose, arabinose etc).

    One could then calculate the maximum amount of linen that is non-carbohydrate, then assume conservatively that it was all modern carbon (including thymol contaminants), and calculate the maximum reduction in radiocarbon age due to possible/maximal contamination. If that were small, say a few decades, one could stop there. Suppose it were not. Suppose the real age could be centuries older based on possible contamination?

    Again, it’s not the end of the world. There are ways of dissolving and re-precipitating cellulose, the main constituent of linen, so one does one’s carbon-dating on purified cellulose instead of whole linen. The advantage of that is one can check the purity of the isolated cellulose by its glucose content (100% of its mass should be accountable as glucose, allowing for water), and even if it’s 99.9%, there’s not enough modern carbon there to throw the dating, whether it’s thymol or something else.

    This should all have been done 20-25 years ago needless to say. If a result is inconclusive one repeats it (and if there are uncertainties re protocol one addresses them, and does not sit wringing one’s hands, or intoning mañana, mañana. There’s an entire industry out there, intent on trashing the 1988 dating, and the reputations of the 3 labs that were commissioned to carry it out. It’s time that nasty little industry was put out of business, even if the result comes back that the Shroud is 1st century AD (or still medieval). If it’s the first, I personally might consider applying for admission to a monastery…

    If a task is once begun
    Never leave it till it’s done
    Be the labour great or small
    Do it well or not at all.

  2. Was anything like thymol around in the 16th century, that without the need for patches and interweaving, or smearing with madder and gum, could have traded carbon atoms with the cellulose of the cloth, thus truly, undetectably, have altered the date?

      1. I’m trying to think where “Scarborough Fair” comes into this (or whether Dan intended this as a response to Anonymous on a different thread re those leaf and other plant imprints). Maybe it’s Hugh’s allusion to “trading” wot dun it (medieval fairs etc).

    1. Excellent point. I’ve often thought that there must have been some attempt at preservation earlier on in the Shroud’s life.

  3. Dan :
    I was thinking about the leech man’s day job steaming thyme near the shroud exhibit.

    Let’s see if senescent brain (mine) is up to the job. “Leech man” refers to our medieval monk with the job of attending to common ailments ( “a good bleed cures all”).

    “Steaming thyme”? Is that what they used to do? Might that release some thymol-like chemicals into the air? Gets into everything – clothes stink of it, including that expensive length of linen that the Master has bought in for goodness knows what, but not got round to using yet…

    Bloodletting? The modern day equivalent is Dan Porter’s site. Stress-testing of ageing and decrepit neurones. Guaranteed to keep Alzheimer’s at bay…

  4. Well, don’t say I didn’t warn you Dan, just yesterday, but I’m not just a tedious old science fart, but someone with a keen eye for politics too (“newsjunkie” etc).

    You know, they used to refer to Gerry Adam’s Sinn Fein as the political wing of the IRA, which I used to mentally translate as ” the IRA is the terrorist wing of Sinn Fein”.

    There is now absolutely no doubt in my mind that shroudstory.com is the political wing of Barry Schwortz’s STERA.Inc. As for STERA? Well, who knows. But if I were a well-funded Shroud-promoting organization, I’d play it smart and put ostensibly non-Catholic folk in there as front men – close to us, but not too close.

    Slick – very slick, and hopefully fairly harmless. Just continue to keep Mark Antonacci’s operation at arm’s length… He is something else – a man with an agenda that could precipitate WW3…

    1. Sinn Fein: Who really were the terrorists? Were they the descendants of people Oliver Cromwell imposed on Ireland? Martin McGuiness was fighting the terrorist group called Ulster Defence Association.

      1. And Martin McGuiness went on to become Minister of Education in the Stormont Government under the Peace Agreement. So who’s the stirrer? You or me? I merely pointed out the way that reality can be airbrushed while there are battles to be fought, with both black and white altered to make pleasing shades of pastel pink (depending on one’s perspective)…

  5. Anyone who knows me knows that I am not a scientist. However if I understand what I have read here and when I looked up just what thymol is – I am of the impression that they were unconsciously sabotaging their own work. It seems to me that for what ever reason and by what ever unknown method that the Shroud has been and is being preserved. I would have to say that it is God’s will for this to be.

    1. So what are you saying? That it’s God’s work, but has been sabotaged to such an extent that no one can prove it anymore, thanks to “contamination” (ring any bells?)

      Hmm. Sounds like a self-serving argument to me. So what else is new in this murky pool called Shroudology?

      I now consult my wife before posting any comment.

      Her opinion is: “What you say sounds like waffle”.

  6. It is wise to advise caution when it comes to another round of carbon dating at this time, and Thymol is only one of the reasons.

    1. There’s no such word as “caution” where scientific experimentation is concerned. Plunge in there. Decide afterwards whether it was a good idea or not.

    1. If that’s a reply to my comment Louis, then I would say this: don’t try to deploy so-called scientific evidence to press the case for authenticity, then claim you are a special case deserving of kid gloves treatment when the going gets rough.

  7. Colin, how many Turin Shrouds are there in the world? The going got rough at the other end with everything, from A to Z, going wrong: from the mess made by scientists Professors Luigi Gonella and Giovanni Riggi (look from where he took the sample!) till the announcement, with that significant exclamation mark after the dates written on the blackboard. It is important to stress that Dr. Michael Tite attended the Round Table convened by Cardinal Severino Poletto and Professor Christopher Ramsey keeps an open mind and is a practicing Christian while believing that the 1988 CD results were correct.
    On my part, I see no need to press the case for authenticity simply because my faith does not depend on relics and even the Church has left the question of authenticity to science. How often have I stated on this blog that even if the TS is proved to be authentic it will still not answer many questions!

    1. Sorry – I’d love to answer your point, but I have the site’s host on my back (so what else is new?). His real beef is that I have fingered him for being a front man for STERA.inc. and goodness knows what else. Time to head for the hills – and plan new strategies for busting open the real agenda that underlies all this insidious and persistent Shroudie propaganda… (Antonacci gives a possible clue, even if he’s at the nuttier end of the spectrum).

  8. Colin, I may not agree with each and every view of the Shroudies you have attacked but I also do not question their seriousness and surely that is the approach of blogmaster Dan? That is obviously the reason why your views as a scientist are welcome here, but, once again, as long as there are no personal attacks, which only serve to bring emotions to boiling points that are not conducive to fruitful discussion. To be fair, that has to apply to everyone posting comments here, so you can calm down, have a glass of Scotch(?) and be prepared for another round of entertaining discussion tomorrow.

    1. Thanks Louis. But I have had well nigh two years in which to calm down as you put it, and have tried my best to do so, But it’s simply not possible. The Shroud is at the forefront of a campaign, and it’s becoming increasingly clear with each passing day what that campaign is all about. The ultimate goal is a minority Christian equivalent of Taliban mind control – this site being soft power. Yes, folk will say more wacky ideas. Well,of course it will seem wacky, because one is fingering a wacky version of Christianity, and being wacky hopefully it will achieve nothing, providing it fails to break out into the big wide world and starts to get backs up.

      We have enough problems out there as it is, without modern day (pseudo-authenticated) Shroud-waving fundamentalists trying to restart the medieval Crusades where our ancestors left off.

  9. Colin, I agree to the extent that Taleban mind control would apply here only if the TS is being used to determine if Christian faith is fact or fiction.

    1. Have you read Antonacci’s agenda? It makes my flesh creep. Talk about would-be religious supremacy.


      Seems the Shroud will now need protecting from hidden neutron-emitters – for fear that Christian Taliban like Mr. Antonacci and his pals come along later with a scanner, declaring that it has all the right isotopic signatures for a 1st century miracle, a report to be sent straight away to Tel Aviv and Mecca.

      Where does the soft-core pro-authenticity end of the spectrum stand on this fundamentalist hard -core variety – that’s what I want to know?

  10. Colin,many of the oldtimers in the realm of Shroud studies have presented a balanced point of view, aware, one presumes, that there is no point in being one-track minded. As commented yesterday, even if the TS is “proved” to be the genuine article it will still not answer many questions, many of which are still to be addressed.

    1. I wish I could be as relaxed and sanguine about it as you are Louis.

      All someone has to do is sneak a mixture of ordinary beryllium and americium-241 (present in domestic smoke alarms) into the cabinet housing the Shroud. That mixture then emits neutrons (half life approx.10 days) and before you know what the Shroud will then be impregnated with radioisotopes such as chlorine-36 and calcium- 41 that Antonacci and his pressure group (if invited in with their scanners) could later proclaim to the world as proof that the Christian story based on Resurrection is proven – and a lot more besides (he reckons, see below ) as to the mechanism of resurrection.

      You think I’m exaggeraing?

      See Antonacci comment from this site in September: (my bolding)


      Please study the keynote address, which can be found on TesttheShroud.com. I’m not trying to be self-congratulatory or subjective, but these procedures could test every explanation for the Shroud’s radiocarbon dating and answer all the mysteries surrounding the Shroud. If the Shroud linen cloth, blood and other particles on it were examined at the molecular and atomic level, you could also collect enough new information that scientists could analyze this data for many years to come. I will be further updating this proposal, as well.

      And on the Petition site:(my bolding)

      A leading hypothesis published in Scientific Research and Essays in 2012 asserts that particle radiation was emitted from the length and width of Jesus’ dead body while he was wrapped in the Shroud, and it was this “event” which caused the unique images on the cloth. Molecular and atomic testing could prove that hypothesis to be true. ……

      …..If unfakable and independent evidence was obtained to confirm this hypothesis however, it could actually be used to analyze the central premises of various religions throughout history and in our world today.

      Objective and independent evidence does not exist to prove the central premises of any other religion, agnosticism or atheism. In contrast, the Shroud of Turin could provide thousands of unfakable items of scientific and medical evidence to prove the central premises of Christianity. This new, incomparable evidence could lessen or remove the underlying bases for many of the world’s ongoing wars and conflicts. The world has everything to gain and nothing to lose by the proposed molecular and atomic testing of the Shroud of Turin.


      There’s a lot I could say, but won’t. For now I think that the cabinet that houses the Shroud should be fitted with a neutron detector and a web cam link that allows anyone anywhere in the world to check at any time that it is not detecting neutrons.

      1. Would the sabotage you are mentioning lead to ‘unfakable’ evidence? If there is a way to skew the evidence then doesn’t this demonstrate the evidence is indeed fakable? And now that skeptics like yourself are aware of the possibility of sabotage, this would undermine authenticity claims based on said testing.

        For myself, I share your fear. There is a segment of Christianity that pushes a Christian triumphalism and the Shroud could be be exploited by them. The thought that Christians would use the Shroud to proselytize turns my stomach. It has been called the Silent Witness…that is exactly how it should be seen. If God wanted it to preach he would have added audio to it.

        Hmmm, that makes me wonder… could there be audio properties encoded in it? Who needs flowers and coins when you could have music and soundbites. :)

      2. Colin, one has to be as relaxed and sanguine as possible when discussing the TS, where there are passions on both sides. Blowing our tops only impedes one from thinking clearly.

  11. David Goulet :
    Would the sabotage you are mentioning lead to ‘unfakable’ evidence? If there is a way to skew the evidence then doesn’t this demonstrate the evidence is indeed fakable? And now that skeptics like yourself are aware of the possibility of sabotage, this would undermine authenticity claims based on said testing.
    For myself, I share your fear. There is a segment of Christianity that pushes a Christian triumphalism and the Shroud could be be exploited by them. The thought that Christians would use the Shroud to proselytize turns my stomach. It has been called the Silent Witness…that is exactly how it should be seen. If God wanted it to preach he would have added audio to it.
    Hmmm, that makes me wonder… could there be audio properties encoded in it? Who needs flowers and coins when you could have music and soundbites. :)

    “If God wanted it to preach he would have added audio to it.”

    Each new Pope can generally be relied upon to provide a respectful voice-over and the recently outgoing one even organized a final farewell to camera leaving little room for doubt as to where he stood on authenticity. Pope Francis has been criticized, of course, for use of the term “icon” when it should have been Holy Relic. As you can see, I trawl some pretty murky places in the blogosphere to dredge up this kind of stuff… Know thy opponent… Or is it a case of keeping up with the Jones? ;-)

  12. There is nothing wrong with researching and finding better ways to live in this world that diven to us to live in and use for the betterment of mankind in his physical existence, However, there is something about the way some of this research into just how the Shroud is portrayed or demonstrated to still be in existence. Something about some of the writings brings to mind the 1st book, of the Bible and the Tree of Knowledge. Mankind wanting to learn to be as God.

  13. Since no measurements were made, attempting to carbon date the Shroud once again cannot really be relied upon to date it. That is the point of Rogers’ work and of Barrie’s caution. To carbon date it might be of interest, but really cannot accurately predict the age since this chemical was administered with no measurements.

    1. Thyme, at any rate, if not thymol, has been used as a preservative since antiquity. Does anybody know if any other carbon dates are considered to have been skewed by a subsequent application of thymol?

      1. No, Hugh, but am I the only one with some knowledge of organic chemistry to wonder what all the fuss is about? A close reading of Rogers has him referring mainly to the physical adsorption of thymol to wood initially, then to the cellulose of linen, and only at the end of the passage does he in passing seem to be implying a chemical bonding to linen. But why? Thymol and other phenols with their aromatic (weakly acidic) OH group should not show a bonding tendency towards other hydroxylic compounds, certainly not cellulose, the major constituent of linen, in which the -OH groups are in any case hydrogen-bonding with one another, explaining the enormous chemical resistance of the cellulose fibres. I for one would have had no hesitation in filtering a reaction mixture with phenols through Whatman filter paper.

        It would be the easiest thing in the world to take some old linen or paper, treat it with thymol, and see whether the dating is affected. My guess is it will not be appreciably, because thymol will only adsorb physically, and will be removed by the clean up procedures, which is what they are designed for.

        I’m getting increasingly suspicious of these claims that radiocarbon dating is rendered invalid due to the likelihood that X,Y or Z is present and presents an insuperable contamination problem. I would say to those people – consult with chemists before making these ex cathedra pronouncements (and don’t take everything Mr. Raymond Rogers RIP said as Gospel truth either).

  14. I’m glad you said that. I’ve come across this: “The Late Glacial and Holocene development of vegetation in the area of a fossil lake in the Skaliska Basin (north-eastern Poland) inferred from pollen analysis and radiocarbon dating,” by Piotr Kolaczek et al, in Acta Palaeobotanica (53(1). The authors find that their radiocarbon dating of old peat bogs was improved by treating their macrofossils in glycerine-thymol-ethyl alcohol mixture, and then rinsing them with alcohol. They say: “The interesting fact is that most of the dates from the Skaliska Basin carried out from macrofossils treated by a mixture of glycerine, thymol and ethyl alcohol (but pretreated by rinsing them in alcohol) reflected a reliable age in comparison with that deduced from palynological analysis. The aforementioned observations give a far-reaching possibility of dating profiles investigated in the past, from which macrofossils have already been identified and collected (and thus preserved in glycerine-thymol-ethyl alcohol mixture).” They clearly do not think that even ancient (3000 BC) material is likely to be ruined from a radiocarbon dating point of view by preserving it in thymol, so 2000 year old material would be even less so.

    1. Yes, I suspect there’s an assumption that being a powerful germicide, phenol must be chemically reactive, by analogy with bleach etc. But from my limited reading on the subject, phenol and its close relatives like thymol work by an entirely different principle, namely by staying intact and embedding themselves in biological membranes, messing up all the processes that depend on the the correct electrochemical environment for crucial processes like ion transport and uptake, oxidative phosphorylation etc.

      If it were chemically-reactive it could never have been used in vapour form to fumigate operating theatres etc. prior to antibiotics. Sure, there were side effects (lung irritation) but phenol (and thymol) have never been linked to cancer as far as I’m aware, which would be the case if it chemically modified DNA etc.

      If someone is to claim that substance X cannot be removed from linen by standard de-contamination procedures, they should provide evidence to back that view. It’s not rocket science – simply buy the suspect chemical tagged with a radioactive marker like C-14 or tritium and see whether it sticks to linen – and resists desorption by acid, alkali, alcohol etc….

  15. For those who have the book (“A chemist’s perspective etc…), please read p.131 and 132.

    Rogers explains in detail the effects of Thymol on the Shroud, not only for a new radiocarbon dating (“A significant amount of reaction will totally destroy the option for making accurate radiocarbon age determination on the cloth”, suggesting that the standard cleaning process can not remove the new carbon: “the Thymol that has reacted with the linen can not be removed by any safe method”), but also for new studies of the blood and of the fabric itself.

    Rogers wrote: “Being a phenol, Thymol as a -OH group attached to a benzene-type ring. The aromatic ring makes phenols more strongly acid than alcohols. They are very polar, and that is why they adsorb so strongly and react irreversibly with so many materials (..)”
    ” Given enough time, phenols will form ethers with other -OH groups, and a major part of cellulose is hydroxyl groups. Cellulose is made of sugar units. These ethers are very stable (…), and you can not reverse their formation without destroying the cellulose. Hydriodic acid (HI) is usually used to open phenolic ethers. HI would destroy the structure of the cloth”

    Rogers concluded: ” “Thymol will react with the Shroud ! Was the Shroud lucky enough to avoid massive effects ? Only time will tell.”

    Maybe the answer to this question could be found, performing the experiments suggested in comment # 1 ?

  16. “The aromatic ring makes phenols more strongly acid than alcohols.”

    Yes, but they are still exceedingly weak acids.The pKa of thymol is 10.6 approx. Compare with acetic acid – 4.8.

    “They are very polar, and that is why they adsorb so strongly and react irreversibly with so many materials (..)””

    Since when has polarity been a factor in reacting irreversibly? Coming from a chemist that statement is incredible.

    “Given enough time, phenols will form ethers with other -OH groups”.

    Yes, if you reflux in a laboratory flask, probably with acids or other accelerators, catalysts etc.

    “…and a major part of cellulose is hydroxyl groups. Cellulose is made of sugar units.”

    Cellulose is celebrated for its chemical inertness, due to interchain hydrogen bonding. I’ve seen a paper with the title “Cellulose has no free hydroxyl groups”. Why do chemists use cellulose as filter paper, unless its chemical inertness can be relied upon when dealing with most chemicals except for the cuprammonium reagent and powerful oxidizing agents, like conc. H2SO4 and HNO3.

    I hate to say this, but having read those comments, my regard for Mr.Raymond Rogers RIP, thermochemical explosives-testing specialist, is now in free fall.

  17. I’m sure Rogers is theoretically correct, but he leaves us with one of those “would” situations which I should like experimentally verified. Thymol is far from obscure, and presumably used by the shroud conservators because they had used it before for other things. Has any radiocarbon lab complained about it? As you can see, the only reference I can find is all in favour of it.

  18. “I’m sure Rogers is theoretically correct”

    Here’s the email address of the American Chemical Society.


    I invite folk here to seek an impartial opinion as to who is right, who is wrong. I say that thymol would have little or no chemical reactivity towards other hydroxylic compounds, except under extreme laboratory conditions, and the chances of it reacting chemically with cellulose under ordinary environmental conditions to form covalent or even much weaker hydrogen bonds are essentially zero.

    Yes, thymol can physically adsorb (a principle exploited in paper chromatography) but that’s something entirely different. The clean-up procedures used in sample preparation for AMS-C14 dating should be able to strip off, aka “elute”,substances that are merely physically adsorbed, simply by steeping in acids, alkali, organic solvents etc that alter the polar/apolar balance between cellulose and adsorbed molecules, and, importantly, with little or no risk of degrading cellulose, it being chemically inert towards most molecules (and no more likely to form covalent chemical bonds with thymol than with any other ordinary everyday chemicals, phenols included).

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