This is part one in a series of posts about wine closures. In this series, we’ll explore the relative merits and drawbacks of the many different ways we seal our wine.

The pop of a cork is almost as synonymous with wine as the subsequent pouring, swirling, and slurping.  Sometimes, though, the magic of this familiar ritual is ruined by the revelation that a bottle of wine is … well, “corked.”

There are lots of reasons for cork’s dominance of the wine bottle closure market. It naturally has many physical and chemical properties that make it ideal for sealing a wine bottle, including providing a decent barrier against transmission of oxygen in wine. It’s not without its shortcomings, though, including contributing to bottle variation and, of course, the dreaded cork taint.

Cork as a Natural Product

Harvested cork.
Image via Wikipedia

Cork is harvested from the bark of the cork oak, Quercus suber. Vast forests of cork oak cover millions of acres in the leading cork producing countries of Portugal and Spain, and many animals, including the endangered Iberian lynx, make their homes in the great forests. Unlike most trees, harvesting the bark does not kill cork oak trees, allowing for many cork harvests from a single tree over its lifetime (some trees can be productive for over 200 years), so cork production is widely regarded as a highly sustainable enterprise.

The cellular structure of cork contains a material called suberin, a waxy, complex polymer that contains oil-like carbon chains, polyphenols, glycerol, and other components. Suberin makes the cork impermeable to water and gives it a low gas transmission rate, keeping oxygen out.

Demand for cork is largely driven by demand for cork wine bottle closures, and in recent years alternative closures like synthetic corks  have taken a large chunk out of natural cork’s market share.  Around 70% of the roughly 18 billion bottles of wine produced worldwide are sealed with natural cork, down from 90-95% in the 1990s.

Cork Taint

Chemical structure of 2,4,6-trichloroanisole (...
2,4,6-trichloroanisole, via Wikipedia

Since its discovery as the main contributor to cork taint in 1982, much has been written about 2,4,6-trichloroanisole, which is thankfully abbreviated as TCA. Its aroma has many descriptors, including earthy, moldy, and musty, but my favorite is “old library books.”  Estimates vary as to how many bottles have mustiness at detectable levels.  Cork industry estimates put the number at under 1%, but other sources have placed it anywhere from 3% (International Wine Competition Wine Faults Clinic, 2005), to 7% (James Laube, Wine Spectator, 2009).

Cork taint arises in cork through the action of microorganisms that live in the lenticels (the dark spots). It’s thought that chlorinated products used to bleach and decontaminate corks react with phenolic compunds in the cork to create chlorophenols, which are toxic to these microorganisms. They fight back, though, by detoxifying the chlorophenols, producing chloroanisoles like TCA. Any winery that uses chlorine-based products for sterilization puts itself at risk of TCA contamination.

Humans can detect TCA at very, very low levels; anywhere from 1-10 parts per trillion (nanograms/liter). That’s not very much at all. One half-milligram of the stuff would cause an Olympic-sized swimming pool to smell like a musty basement. Its perception varies based on wine style, and at similar levels it’s more likely to be detectable in white wines than reds. Interestingly, it’s thought that TCA and other similar compounds are indicators of potentially harmful fungal growth on food, so it’s no wonder humans are good at detecting it.  TCA itself, though, is harmless.

The cork industry, after a long period of denial and PR-based solutions, has finally started to take action against TCA. Chlorinated treatments have been replaced with hydrogen peroxide, boiling processes have been updated, and many steps have been taken to curb microbial growth during the cork manufacturing process. Still, even though cork has cleaned up its act a bit, cork taint persists.

Other compounds can also be responsible for “corked” wine, including 2,4,6-tribromoanisole (TBA—not to be confused with trockenbeerenauslese), which can also throw off a musty aroma. TBA is a cousin of TCA, where chlorine has been replaced by a chemically related halogen, bromine. In this case, the creation of TBA is similar to TCA, though the source of the bromophenols is slightly different. 2,4,6-tribromophenol (TBP), the precursor to TBA, is frequently used as a fungicide,  fire-retardant agent, and wood preservative. Ambient microorganisms in the winery could be producing TBA from TBP on wood structures, laminates, or pallets. The TBA, once in the air, could make its way into wine. In this way, a wine could be “corked” without the cork.

Chemical structure of 2,4,6-tribromoanisole
2,4,6-tribromoanisole, via Wikipedia

While cork apologists might argue that this systemic taint could happen with any closure (like cork, plastic synthetic closures and screwcap liners have a high affinity for TCA/TBA when it is released into the atmosphere), the fact that ambient TCA/TBA can enter wine does not completely remove the cork from blame. For example, in major wine competitions, the presence of mustiness in a wine sealed with a synthetic or screwcap closure is very rare, so while taint from winery sources is possible, it is likely not widespread. Even so, TBA has only been confirmed as a cork taint compound recently (2004), and there are few studies that can be used to determine its relative prevalence.

Wine writer Jamie Goode, in his book Wine Bottle Closures, argues that the continued presence of cork taint, even with the elimination of chlorine sources, may imply that the taint is simply endemic to cork itself. Other compounds can also contribute to cork taint, such as geosmin (which smells strongly of spinach and earth and comes from the use of moldy grapes) and the recently elucidated MDMP (2-methoxy-3,5-dimethylpyrazine), which is produced by a bacterium that grows on cork and oak wood.

Natural Variability

As an agricultural product, cork is subject to some variability. This variation in the cork itself can produce a lot of variation in the performance of cork as a closure. When bottles are stored upright (and cork is allowed to dry out) its oxygen transmission rates can vary up to 1,000-fold. The variability drops when bottles are stored horizontally, but the natural variation still holds at 2-3 fold differences in individual corks.

This inconsistency in oxygen transmission rates (coupled with the random probability of cork taint) unquestionably contributes to bottle variation in wines. Meanwhile, synthetic closures and screwcaps are generally very consistent in their performance.

The Future of Cork

Cork is a remarkable product. When at its best, it allows just enough oxygen for wine to age in a slow, controlled way. However, at its worst, it can be inconsistent and, if tainted, ruin a wine. The cork industry is aware of the problems that cork taint causes and is certainly cleaning up its act.

But what is an acceptable rate of TCA appearance? One percent would still render 126 million bottles of wine undrinkable. Even if the taint is not identified by the consumer, a winery runs the risk of a novice consumer thinking that it was not the cork, but the wine itself that was bad. Furthermore, even if the taint is not detectable (even by an expert), sub-threshold levels of TCA could still affect perception of fruit. Plus, detection thresholds for TCA vary from person to person. While some might be able to smell a corked wine from across the room, others will happily quaff without qualms, so defining a standard for acceptable TCA levels (one that isn’t “zero”) is quite difficult.

There is hope for cork producers, though. As wineries strive to become increasingly “green,” many see cork as the sustainable way to go. Chlorinated products have been in disuse for roughly a decade, so perhaps when newer crops of bark come up (the trees take 9-12 years to develop the layer of cork), cork taint levels could decrease. Increased understanding of the compounds that cause the musty aroma can also help wineries to tackle this problem.

Tom Mansell

Tom Mansell is a PhD candidate in chemical engineering at Cornell University in Ithaca, NY. He is borderline obsessed with the science of wine and winemaking. His blog, Ithacork, focuses on Finger Lakes wines and always includes a “Science!” section, which gets down to technical details for the hardcore wine geek. He is also the Science Editor for The New York Cork Report. Follow him on Twitter @mrmansell.

About The Author

Tom Mansell
Science Editor

Tom Mansell is the Science Editor here at Palate Press and a member of the Editorial Board. He has a PhD in chemical engineering from Cornell University, where he also learned to love the wines of the Finger Lakes. He is also the Science Editor for The New York Cork Report. Tom is currently living in Boulder, CO, where he is a researcher at the University of Colorado. Follow him on Twitter @mrmansell.

  • Pingback: Tweets that mention Tainted Love: A Look at the Role of Natural Cork in Wine : PALATE PRESS -- Topsy.com

  • Pingback: Tweets that mention Tainted Love: A Look at the Role of Natural Cork in Wine : PALATE PRESS -- Topsy.com

  • Pingback: Wine Wines @ everything! » Blog Archive » Tainted Love: A Look at the Role of Natural Cork in Wine – Palate Pres

  • http://blog.bastianich.com Wayne Young

    It’s interesting to see at the top of the article the mention of how certain natural substances in cork “keep oxygen out”, yet further down the mention of “it allows oxygen to enter in a slow, controlled way”…

    The basic question is:
    Is aging wine in bottle an aerobic or anaerobic process? Great Ports were often sealed with wax… Is there ANY oxygen getting through that layer of wax? Could that be one of the reasons they age so well?

    Someone smartrer than me can answer this question, but I know plenty of winemakers here in Friuli who feel that a bottle needs to be CLOSED, Period, and that oxygen transmission through cork is PR spin.

  • Pingback: Tainted Love: A Look at the Role of Natural Cork in Wine : PALATE PRESS

  • http://www.vtwinemedia.com Todd Trzaskos – VT Wine Media

    Ken Payton had a great article on the topic last week,
    http://reignofterroir.com/2010/12/05/hacking-a-wine-the-new-science-of-cork-taint
    and he’s advocating a new terminology to replace ‘corked’. I agree that it is only fair to the poor old cork, which has been our friend for so long.
    Halo Anisole Contamination –
    HAC’d does have a nice ring to it…

  • George

    During my sole “corked” incident, I looked inside the bottle as I determining what was the source of the musty smell. I saw a small swirl floating film. The odor and taste was distinctly musty.

  • http://ithacork.com Tom Mansell

    Wayne:
    Great point. The role of oxygen in winemaking and aging is very complex… I’ll be addressing it more when I talk about screwcaps.

    The basic answer is no closure is completely oxygen impermeable, and each closure has different oxygen transmission properties. Cork was the dominant closure for so long that we became very accustomed to the way that wines aged under it, but the jury is still out on aging with screwcaps, which let in far less oxygen than cork.

    Many styles of port undergo controlled oxidative aging before bottling, which could explain their longevity. Also, the 18% alcohol probably helps.

    Todd:
    Thanks, I had linked to Ken’s piece at the bottom of the article. Cork has been both a friend and foe to the industry. And while mustiness may not come from the cork ALL the time, it’s safe to say that the cork is at least partially responsible most of the time. Unfortunately, I don’t think we’ll ever stop calling it cork taint.

  • http://www.phillywine.com Mark Cochard

    Wayne, You should read up on the AWRI’s ongoing closure trials. In essence they test the wines at periodic intervals measuring the level of SO2 remaining in the wine as an indicator of the effectiveness of the closure.
    Jamie Goode has a good article here
    http://www.wineanorak.com/closuretrial.htm
    From AWRI
    http://www.awri.com.au/commercial_services/packaging/closure_assessments/
    And another link
    http://www.awri.com.au/commercial_services/packaging/closure_assessments/
    And Another
    http://www.wineanorak.com/oeneo_closures_debate_2006.pdf

    There are also several books out one by George Taber and the other by Tyson Stelzner

  • http://www.phillywine.com Mark Cochard

    Tom
    “Great point. The role of oxygen in winemaking and aging is very complex… I’ll be addressing it more when I talk about screwcaps”
    I was typing as you posted this, Did not mean to usurp one of you upcoming articles.
    Mark

  • http://reignofterroir.com Ken Payton

    Mr. Mansell, you miss the point about TBA entirely. Cork apologists? Good lord. What kind of scientist are you? You write, “there are few studies that can be used to determine its relative prevalence”. Well, rather the point, I’d say. But is also has to do with contaminated barrels, pallets, and a wide variety of plastics brought into an otherwise clean environment.

    To claim “[...] while mustiness may not come from the cork ALL the time, it’s safe to say that the cork is at least partially responsible most of the time. Unfortunately, I don’t think we’ll ever stop calling it cork taint” is nonsense. Where is the warrant? Where is the evidence? Silly, sloppy work, Mansell.

  • http://reignofterroir.com Ken Payton

    Mr. Mansell, your article is far too brief and unclear. Your presentation of TBA is inadequate. And your characterization of cork taint researchers as ‘apologists’ is both unscientific and insulting.

    Further, to say “while mustiness may not come from the cork ALL the time, it’s safe to say that the cork is at least partially responsible most of the time. Unfortunately, I don’t think we’ll ever stop calling it cork taint” is without scientific warrant. It is merely a personal statement. I think you do a disservice to the culture of science, especially when you’re but a mere PhD candidate.

  • http://www.winemakernotesblog.com/ John Kelly

    Well done piece, Tom. But as it seems these articles so often go, the emphasis on the fraction of bottles that are damaged by cork is given far more weight than the majority of bottles that are enhanced by cork.

    I have long hypothesized that the extractables from natural cork are responsible for more chemistry than that from oxygen ingress, and that the flavor of cork (no less than the flavor of oak barrels) is ingrained in our cultural sub-conscious as part of the recognized sensory profile of fine wine.

    That is not to say there are not many fine wines being bottled under screwcaps – there are. But to my palate, the sensory experience of wine with a cork in it has something extra, and most often positive.

  • http://www.vinperfect.com Tim Keller

    Nice post, and one of the better ones I have seen on this topic.
    (and thanks to google alerts I read them all!)

    I can answer Wayne’s question as my company is developing a controlled oxygen liner for screwcaps. I have been a napa / sonoma winemaker for 12 years and am now dedicated entirely to solving this very problem.

    The answer to the question about oxygen is: “Wine needs very little, but Zero is not the right number either.”

    It was luis Pasteur that first pointed out the dual-relationship that wine has with oxygen. Some is necessary for the wine to mature, but too much quickly spoils it.

    Here at VinPerfect, we are working at delivering within the range of .5 to 1.5 ppm of oxygen into the bottle per year. VERY small amounts – but not zero. What we are doing is not high-tech necessarily, but it requires high precision to target a range that small over such a long period of time such as a wine enjoys.

    As far as the wax, most polymers are almost transparent with regards to oxygen. The cork would be as well, but it benefits from the fact that it is so thick in regards to the distance oxygen needs to diffuse through.

    That said, it is wise to take the quality claims of the cork business with a grain of salt:

    - Corks deliver moderate oxygen on average, but what you get from a particular bottle is essentially random – you can have oxidation or reduction or anywhere in between. Only a minority of bottles actually fall into the “moderate” oxygen category.

    - What is the defect rate that is acceptable in other food products? Is it enough that TCA levels are lower than they used to be? Or if the problem is avoidable, isn’t ANY level unacceptable? Is tradition more important than quality?

    - Meditate on the conservation message of the cork folks. How exactly are those forests in danger if we stop using cork? Whose hands would be on the chainsaw? Is the ruining of 10 billion dollars worth of wine every year really the best way to protect that ecosystem?

    - Look up where the Iberian Lynx is, why it is endangered, and where the cork forests are. You will see that corks have nothing to do with the issue of the lynx.

    Like everything in the internet age, we need to question the facts that are handed to us. In this particular case, the only people producing facts are those protecting their interests. So make sure you keep your brain on when evaluating what they say.

    Thanks for a good, well researched post!

  • http://ithacork.com Tom Mansell

    Ken:

    On the subject of brevity, I agree. That’s why I decided to expand the closure conversation into a series. Entire books can be (and have been) written on the subject.

    I’m sorry you interpreted “apologists” as pejorative. An apologist is merely a defender.

    Finally, in response to systemic TCA/TBA taint, if this is really the problem and if cork is really not the main source of these taints, then where are all the bottles tainted by synthetic cork? Where are all the corked (HACked?) screwcaps?

  • http://www.pauljkiernan.wordpress.com Paul

    Don’t know if people caught this http://pauljkiernan.wordpress.com/2010/12/12/cork_promo_spoof_ad/ . Funny promo video from 100% Cork promo group.

    p.s. Sorry for the self plug!

  • Pingback: Everything You Ever Wanted To Know About Cork & Cork Taint But Were Afraid To Ask | BoozeNews

  • http://ithacork.com Tom Mansell

    John:

    There are other extractable volatiles in cork, you’re right. Vanillin is one of them, which possibly comes from the degradtion of lignin in the cork.

    http://www.ajevonline.org/cgi/content/abstract/49/1/6

  • http://www.vinperfect.com Tim Keller

    I actually thought that Tom’s treatment of systemic TCA / TBA issues was exceedingly fair and encapsulated the issue very well.

    I have seen plenty of people point to systemic problems and suggest that they mean that cork is not to blame. But there is no evidence to support that.

    I know of two wineries here in CA that took major steps to eliminate a in-house TCA issue, and there are others that have probably cleaned up without alerting others to the problem in the first place.

    But this much is clear: If the winery has a systemic infection, then every bottle will be “corked”. This is simply not what is being experienced in our industry. Instead, you find one corked bottle, open another and the other is fine. In that case the blame can only rest on the cork.

    While on the subject, I would point out that in the “future of cork” part of this post, which suggests that stopping the use of chlorine will have it’s effects borne out over the next decade, is giving cork too fair a shake. Yes it takes that long for a tree to regrow it’s bark, but the chlorine was used in processing the harvested cork – not on the trees, so that change should not have a lag time in the production cycle

    What we have in corks today, especially with the stepped-up sampling procedures the modern industry have adopted, this is as good as it’s probably going to get.

  • http://www.winemakernotesblog.com/ John Kelly

    @Tom: should not be taken to imply that vanillin is the only extractable, nor that long contact between cork and wine does not create new extractables.

    @Tim: “…giving cork too fair a shake.” Really? How very self-serving. ;-)

    @Ken: “…you’re but a mere PhD candidate.” Whoa buddy. I resemble that remark. I am also but a mere PhD candidate, albeit one with over 25 years professional winemaking and research experience on top of it. Where can I find your bona fides on your site? Focus on the issues. Unless this is sort of an inside joke between you and Mansell – it that case, party on.

  • http://www.winemakernotesblog.com/ John Kelly

    also @Tim: “…the chlorine was used in processing the harvested cork – not on the trees…” I have been told that halogenated pesticides have been sprayed on cork oaks for decades and that only recently has this protocol been abandoned.

  • http://reignofterroir.com Ken Payton

    @ Mr.Keller, there are a wide variety of pesticides and fungicides that contain chlorine. Many are environmentally persistent. The idea behind the re-growth of cork bark is that many of the more damaging ones, PCBs for example, have been removed from use. Therefore one could expect to see a decline in the formation on TCA in the cork bark itself from some of these agents. As you should know, often cork planks themselves were already TCA tainted by virtue of methylation in the wild, as it were. Chlorine in the processing facility aggravated, but was not the sole cause off its subsequent presence. Thankfully all are on to this matter of basic chemistry.

    @ Mansell, had you thoroughly read my article and comment you would have seen Dr. Ron Jackson’s remark that most folks, despite bs about theoretical levels of taint detection, cannot not detect TCA/TBA well beyond 200 ppt.

    As to why there is an absence of tainted bottles under screw cap and plastics stoppers, well, it is simply not expected and, therefore, an average or poor wine is simply felt to be a function of the wine and not the stopper. Should we be surprised that expectation and suggestion might play a role? The advertisement industry thrives on conjuring invisible values. And the reverse is equally true. Take the toxins in screw cap liners. I spent very valuable time with Dr. Paul White just this weekend. I suggest you read his work. I won’t bother to link it because I think the effort to find his material is a good exercise for an aspiring scientific researcher.

    Further, there are well-documented cases of TBA taint of entire barrels of wine. So the question becomes who is bull shitting who? The screw caps industry would have you believe they are without faults. But that is not the point. The point is that wine contamination comes from multiple sources within the winery and from materials (barrels, cardboard, plastics etc.) brought into an otherwise clean winery. This is an undeniable fact. The evidence amply demonstrates it. So to pretend, as you do, and in the absence of any quantifiable evidence that TCA is the scourge in the majority of cases is without merit and intellectually dishonest.

  • http://reignofterroir.com Ken Payton

    One sentence above should read “@ Mansell, had you thoroughly read my article and comment you would have seen Dr. Ron Jackson’s remark that most folks, despite bs about theoretical levels of taint detection, cannot detect TCA/TBA even up to and beyond 200 ppt.”

  • http://reignofterroir.com Ken Payton

    @ John Kelly With all due respect, I’ll write as I see fit. I suggest you read a Monsanto tech. piece, maybe one of hundreds written on the harmlessness of PCBs. Composed by scientists, there was no transparent equivalence of scientist and truth. Science, whether of tobacco, birth control devices, estrogens, or pesticides, routinely distorts the truth.

    As for my boni fides, by that argument you would be equally disallowed from contributing to the topic at hand.

  • http://reignofterroir.com Ken Payton

    @Keller, PCB is not a pesticide, of course.

  • http://www.winemakernotesblog.com/ John Kelly

    @Ken Payton: With all due respect you are welcome to write whatever you see fit to, but hmmm… I know I’m only a trained biochemist and a guy who has been using and doing technical research on different wine closures for my entire career as a wine professional – not sure how that disqualifies me from the discussion. I’m not going to get into a pissing match with a guy who won’t disclose what qualifies him to participate. You want to do the ad hominem bullshit? I’ll call you on it as I see fit.

  • http://www.vinperfect.com Tim Keller

    I had never heard of chlorinated compounds being sprayed in the oak forests. If that is the case then what you say would be true and my attempt at a “correction” would be mis-guided.

    Since I don’t have information either way on that, I will withdraw the comment.

    However, the lack of sufficient evidence to make a conclusion should be upheld throughout any conversation where people are claiming cause and effect relationships. In the case of systemic TCA exonerating the cork, I think it’s improper to accuse someone of intellectual dishonesty for sticking to the information avaliable.

    Yes, TCA can enter a winery from other sources, yes it can be made on-site from the combination of chlorine and other chemicals such as wood preservatives. (from treated wood beams – not the pure oak in barrels. I have put my nose in many many thousands of barrels in my career and never smelled TCA)

    But there is no evidence, and there is no suggested mechanism for how that contamination could work it’s way into some bottles and not others. If we want to stay intellectually honest in the conversation, we should stick to what we KNOW.

    Stating that we are not seeing screw capped and synthetic cork TCA issues only because we are not looking… B.S. My nose looks every time. So do most others. If that were a problem it would have been noticed by LOTS of people by now.

    What we do know? That many bottles sealed with cork are contaminated, and that if you order another, the next bottle is normally clean. I have made wine for over a decade, and I have drunk a lot of my own juice because I always have a lot of it. I have found corked bottles more often than I am happy to say, and when I open the next one – it is fine. You just cant blame a systemic infection for that. There is no logic to support it.

  • http://ithacork.com Tom Mansell

    Tim: Yes, Chlorine (and hopefully bromine) have been eliminated from the manufacturing process, but polychlorophenol (PCP) pesticides still exist in the environment. The cork bark is essentially a big lipophilic sheet, and over the years of the tree’s lifespan has been known to accumulate PCPs in the bark itself, where the filamentous fungi detoxify them into TCA, TeCA, and PCA (tri, tetra, and pentachloroanisole, respectfully).

    The use of PCPs in Europe is under strict control, but as of 2007 they had not been completely banned in Spain or Portugal.

    http://www3svil.unicatt.it/unicattolica/istituti/enologia/allegati/art_royalsocialchemistry.pdf

    John:

    The aging of wine is still largely an open field of research. There are so many chemical changes that it’s tough to make any conclusions about whether the cork contributes over that long of a time. Interesting hypothesis though.

    And for the record, I’ve never met Mr. Payton, though I submit that the burden of proof is on him that systemic taint is as or more important than flawed closures.

    Ken:
    I did read your article thoroughly but I’m more inclined to believe the large number of scientific studies where TCA’s threshold averages in the 5-50 ppt range. I assume the 200ppt number comes from the Suprenant & Butzke work, where an experienced panel detected it at 17 ppt while an inexperienced panel detected it at 210 ppt. Experience seems to matter in the detection. And I did mention that detection thresholds for TCA vary.

    Never do I claim “in the absence of any quantifiable evidence that TCA is the scourge in the majority of cases” You seem to think that all TBA comes from the TBPs converted to TBA in the winery environment, when the same enzyme that converts TCP to TCA is responsible and is found in cork fungi! Can corks not be tainted with TBA before they enter the winery? It seems just as likely given the ubiquity of TBPs.

    There is some data on this, a masters thesis from South Africa (https://scholar.sun.ac.za/handle/10019.1/2092) where 28 samples identified as “corked” were tested for TCA, TeCA, PCA, and TBA, and TBA was not found above 0.5 ppt in any of them, while TCA was found in most above 3 ppt, with slight contributions of TeCA and PCA. It’s a small sample, but interesting data nonetheless.

    As we discover new molecules that could be responsible, we have to check for them. MDMP, which is produced by bacteria isolated from corks, could also be a contributor.

    Also, thank you for your assigning me some reading as an exercise. I’m sure it will benefit my academic career. From where did you get your PhD?

  • http://www.theoregonwineblog.com Clive

    Ken Payton, my apologies but you’re really coming off as a bit of an asshole, sorry I know that’s pejorative. I may only be a wine consumer and hack writer for a wine blog, no PhD, but I can tell an asshole when I see one.

  • http://www.cgcw.com Charlie Olken

    I have come to this discussion quite late in its evolution, and I am greatly saddened to see some of my favorite people uncomfortably engaged in pitched battle in ways that are getting personal.

    We all get personal at times, even when we try not to, but I wonder if the smart folks here and personal friends of mine like Ken P, John K and even Mr. Mansell whom I do not know but whose writings I find to be thoughtful and insightful could all take a step back and discuss the issues as issues.

    I may not help by making the following observation, but it is an observation borne of pulling hundreds of thousands of corks over the years in my role as wine critic. Admittedly, I am no sceientist and no cork expert. I do know the following, however.

    Cork taint or HAC has decreased over time from a high of something new 3-4%, and maybe higher at times, in my tastings to nearer 1% now. The percentage of wines under screw cap, plastic plug and Diam type closures that exhibit HAC has been and continues to be lower than in wine closed with (natural) corks.

    [I personally dislike the term "natural" cork. Cork is cork. Plastic is plastic and it is not cork.]

    I also think there has been a gradual lessening in the incidences of HAC from non-cork sources, just as there is now a decreased level of brett, a decreased level of ethyl acetate spoiled wine, etc. The industry is getting smarter because it has to.

    The simple test for cork taint is the opening of a second bottle. At the peak of the cork taint problem, we would experience a second problem once in every twenty or thirty of the second samples. Now, it is so rare that it is hard to remember when it last happened. But, in those bottles retasted, the vast majority of second bottles have had no noticeable HAC. Hence, I find myself in complete agreement with the notion that cork taint is the major force in the production of HAC contamination in wine. Spoiled batches do exist. We have seen wineries go into massive top to botton housecleanings to solve seeming HAC problems.

    But, that said, when second bottles show no evidence of HAC, then my conclusion is that the cork was the most likely source of the problem.

    Whether we can agree to that notion or not, I would hope that this conversation, which started as an interesting discussion of the issues, can return to that plane.

  • http://www.palatepress.com David Honig

    Thank you Charles.

  • http://reignofterroir.com Ken Payton

    Good morning from Madrid. I’ve some times before my plane boards, so here goes.

    @Charlie, apologies.

    @Clive, no problem calling you as you see it. But I will add this: Anyone who has spent much time in the academy knows perfectly well it is a contentious, bitchy theater. The idea that scientists and their novitiates dispassionately discuss ideas of the day is not reality. Sufficient intimacy with the internal workings of scientific social cultures actually drove me from the university. For in the university tens of millions of dollars in grant monies are always at stake. Scientist X insists his work is more valuable than scientist Y’s, hence the whispering campaigns, back stabbing, denial of deserved promotion, etc. It is equally important to keep in mind the university is thoroughly compromised by external commercial relations with multi-nationals. Bayer, Cargill, and everybody’s favorite, Monsanto, are hip deep in research programs. But on the other hand, I suppose you’re right. There is little value in performing bits of the theater here. Old habits die hard, I suppose.

    @ Mr. Kelly, imagine the farmer who year after year does what he is supposed to; he adds his synthetic nitrogen, he uses GMO corn, employs his broad spectrum pesticides. Until one day declines in productivity become undeniable, and the health of his neighbor’s fields is similarly troubled; he sees an erosion in water quality; the climate is different then when his father began tilling the soil; his field workers lose their eyesight, come down with exotic cancers, their wives spontaneously abort.

    So, this farmer wonders if there might be a better way. All of his suppliers, each having a raft of scientists with letters after their names, reassure him there is really nothing the matter. Besides, does Farmer John have a lab somewhere hidden in the basement of his clapboard hovel? How can a mere farmer pulling down 50 K a year, with a modest education, possibly know what he is talking about?
    Qualification is the ultimate scientist’s wet dream. It has always been used politically to disable discussion from outside. A woman using a certain birth control chemical may know something is not right with her body, but she just doesn’t have the proper credentials to complain. So, perhaps you will excuse my exuberance, my impatience. Besides, I had requested of David and/or Mr. Mansell that they not post my original comment(s). For reasons known only to them, they did it anyway.

    @Mr. Mansell, the figure of 200 ppt comes from decades of private tastings Dr. Jackson has hosted. Anecdotal to be sure, but I’m sure you’ll agree it counts for something. He did, after all, have the wherewith all to perform proper analysis of a wine after the fact. Moreover, virtually all popular accounts of a tainted wine are accompanied by zero assays. We simply say ‘cork taint’ and the conversation ends. It is therefore irresponsible to say, absent evidence, that a cork was entirely to blame. It has become a cliché, but one quite damaging to the cork industry. And if you read the trades, forums, comment sections of blogs, you quickly see that folks are rarely called on it. It is fine to casually damn an august industry employing thousands and overseeing important environments, but somehow beyond the pale to aggressive push back when one is able. Hilarious!

    This is why I introduced the concept HAC(k)ing a wine. It seemed to do two things: replace casual, blustery certainty with a bit of modesty, and put the blame squarely where it lay, with diverse haloanisoles. To continue to insist on the term ‘cork taint’ in this day and age is ultimately politically motivated, in my view, especially now as biochemical research and subsequent novel assays daily surprise us. Just ‘yesterday’ we learned brain cells can regenerate. Who knew?

    And, again, were one to become a PhD in Mathematics, for example, one could only expect to master a couple of feet of library texts on one’s speciality. Same with ‘Science’. Does the Chemical Engineer have the authority to speak about climate change? Can the Hydrologist weigh in on food safety? A Cosmologist on Nanotechnology? A Neurologist on MicroBiology? It depends what they perceive to be at stake. Can a citizen shout ‘fire’ without knowing of Forestry PyroDynamics? (Just made that science up! A bit of comic relief.)

    A final note. I don’t understand what your getting at here, “You seem to think that all TBA comes from the TBPs converted to TBA in the winery environment, when the same enzyme that converts TCP to TCA is responsible and is found in cork fungi!”
    It seems to be a non sequitur. These are two separate compounds united by a single enzyme. Yes, of course.

    I wish you well in your studies.

  • http://blog.bastianich.com Wayne Young

    @Tom… See that? Ya learn something new every day.. never knew wax was oxygen-transparent!

    The debate is interesting, regardless of the rhetoric. I look forward to future posts regarding the role of oxygen in aging wine.

    Thanks for the post, the chemistry lesson AND the heated debate… I’ll be reading future posts!

  • http://www.winemakernotesblog.com/ John Kelly

    @Ken Payton: thanks for taking the time to come back and clarify. My apologies for going off on you.

    Our worldviews are closer together than you might imagine. For the time being I am a cancer survivor, and I have adequate reason to suspect at least a partially environmental etiology. I recognize that humankind is just one huge random block trial manifesting the effects of over-industrialization.

    I spent this evening sipping a nice Dujac Chambolle-Musigny while reading up on the effects of the Bayer insecticide clothianidin (approved for use on grapes in California and the rest of the country, but never within a mile of our vineyard) and the probability of its role in bee colony collapse disorder.

    Notice I did not say “certainty” or “cause.” I wonder at your characterization of science as some Machiavellian game with an Orwellian language. I will give you that academic politics are Byzantine – that’s the reason I left academia in the first place; not tempermentally suited to the environment.

    But as I have mentioned to Mr. Olken, in my experience science as a discipline is apolitical. People outside science need to be reminded that it is politicians, ideologues, PR flacks, marketers and ethics-free entrepreneurs who routinely distort the truth in the pursuit of an agenda – often just filthy lucre. In my opinion, a scientist who becomes an ideologue or a paid shill is no longer a scientist, by definition – perhaps an administrator, but not a scientist.

    Back about a decade I was technical director for a wine services lab where we regularly analyzed samples for TCA. I don’t recall ever seeing anything as high as 200 ng/L; most samples that we received because they were “suspect” were more like 5-20 ng/L.

    We were brought in to provide expert testimony in insurance cases involving tainted wines. In most cases cork was the source. We did have a couple of cases where the origin was the winery or the bulk shipping container. We did not test for TBA or other compounds that might have musty odors.

  • http://www.palatepress.com David Honig

    Ken, my apologies if I misunderstood your missive:

    “KenPayton – @palatepress @mrmansell I’ve tried on 2 occasions to submit a comment. Both failed, rather like the article itself. Fix it, please.”

    I took that to mean you wanted the comments published, rather than hidden. Based upon your comment, above, that interpretation was incorrect and, but for my error, this kerfuffle could have been avoided. This was obviously my mistake, and I apologize to all for any embarrassment it might have caused.

  • http://ithacork.com Tom Mansell

    Charlie: I use “natural cork” here to distinguish from closures like technical or synthetic corks, though I agree with your sentiment.

    Ken: Re: publishing your comment, as far as I’m concerned, it was submitted when you clicked “Submit Comment.” David and I both responded to your concern at the same time (within minutes of your tweet) and the deed was done.

    Scientists are humans, it’s true, but you can’t pick and choose the science that you accept to be true.

    Finally, down to the technical stuff. Here’s my point about TBP->TBA conversion. You say that because TBPs are in wooden pallets, etc. in the winery, that TBA can manifest itself there via microorganisms that live on the wood. I agree with that. You say that once the TBA is in the winery it can adsorb to the cork. I also agree with that. What you don’t mention is whether TBA could be present in the cork before it enters a winery. Polybromophenols are just as ubiquitous in the environment as polychlorophenols. The same microorgansims in the lenticels convert TCP to TCA as TBP to TBA. Who is to say there is no TBA in the cork bark when it is harvested?

    To call it “cork taint” would imply that the taint, regardless of the molecule in question, would be transferred to the wine via the closure. This would imply that there is something unique about the cork which makes it susceptible to taint.

    Your argument that any closure could be susceptible to this taint makes sense theoretically based on the hydrophobicity of plastic, but again I ask for the evidence of this. While I agree that psychology may play a role (i.e., one wouldn’t expect a screwcap bottle to be
    tainted), it’s not that no one is looking for them. At many large wine competitions, including the IWC, faults are well-documented for all bottles. For them, mustiness in synthetics and screwcaps is exceedingly rare.

    In terms of the language, HAC contamination may more precise, but what of geosmin? What of MDMP, which has been attributed to both cork and oak chips? Would you say to a waiter “This wine has been contaminated with haloanisoles or some other musty compound?” My comment on the future usage of “cork taint” was a personal statement, as these things don’t just change overnight. Until we start seeing significant numbers of tainted wines with alternative closures, my money is still on the cork.

    One could say that wines with systemic taint (e.g., wine from a musty barrel) would not be released commercially (or blended to an acceptable level) and that would explain their absence. This may be true, but it doesn’t address bottle-to-bottle variation, which is the real scourge of TBA/TCA contamination.

    We may disagree on philosophical points, but I think we can both agree that less TCA, TBA, etc. contamination is better for the wine industry. Studies like those from Chatonnet and EXCELL labs help us understand how we can tackle this problem and best deal with it.

  • http://reignofterroir.com Ken Payton

    Just arrived in Chicago from Madrid. Last leg to San Jose will complete my 20 hour day on planes and in airports! But I am not complaining. (Well, maybe just a little.) So apologies for not replying sooner. Anyway, here goes:

    @John Kelly, thank you for your personal reply. I don’t deserve your generosity of spirit, but I will, as I’ve pledged to Charlie, work to be more communicative and less combative. Congratulations on beating the big C. For those of us with a conscience here in Santa Cruz, we witnessed everyday, in my childrens’ elementary and middle school experience, the effects of industrial farming on farm worker families. My outrage at the agro/scientific community has been intensified over the years by direct contact with these families.

    @Mansell, I don’t want to go round and round with you, but I will add this. I am at pains to make it clear that closures are not the only source of TBA contamination. There have been cases of entire barrels of wine compromised before they ever encountered a closure. Further, all closures are capable of absorbing taint compounds without it having anything to do with the nature of the closure itself! This includes the plastic liners of screw caps.

    TBA is a winery environment contaminant readily absorbed by any material. A cork may become contaminated within the winery. That is the point. Subsequent wine spoilage would therefore have nothing to do with the cork per se, just that it was an absorptive medium for a contaminant already present in the winery. The evidence shows that corks nearer the surface or opening of a bag of the same would have a higher probability of contamination were TBA present in a winery. This is equally true of plastic stoppers and screw caps. Variation would be a function of where in the bag corks used on any given day resided. Further (and this is most amusing) a ‘natural cork’ inserted into a bottle of already HAC’ed wine would actually soak up measurable levels of taint! Wild, huh? This means that it is entirely possible a contaminated wine would actually be made drinkable because of the absorptive capacity of the cork.

    Now, the nuances of all of our exchanges I’ve already covered in my HAC(k)ed Wine piece. I feel as if all I’m doing is rewriting it for you! I am a careful writer, after all.

    One last thing: You write, “Scientists are humans, it’s true, but you can’t pick and choose the science that you accept to be true.” Ah, the young. I once thought that was true, too. Dip into estrogen mimics comment boards. Cruise the pages of professional climate change deniers. And as I suggested earlier, read the ‘science’ of Dioxin and polychlorinated biphenyls according to Monsanto’s scientists. Grim. Yes, you can choose the science you accept to be true. It happens everyday. Even here.

    And with respect to the prevalence of TBA precursors in the winery, or brought into the winery, I direct your attention to the ’08 Practical Winery and Vineyard article I linked in my story.

  • http://ithacork.com Tom Mansell

    This discussion has nothing to do with Bayer, estrogen, dioxin, Monsanto, GMOs, or corn. All straw men.

    It is about the relative ability of closures to absorb TCA/TBA or other taint compounds in the winery. Your claim that this can happen in any closure makes sense theoretically, but has not been proven. Your smoking gun would be synthetic and screwcap stoppers on tainted wine bottles… and it simply hasn’t shown up. Your argument is strictly qualitative and what this discussion needs is data.

    This is not a criminal trial of cork. Can any particular instance of cork taint be proven to be the fault of the cork beyond a reasonable doubt? No. But a preponderance of evidence may find it to be so.

    Finally, you said, “Yes, you can choose the science you accept to be true.” If you truly believe this, then there is no point in continuing this line of discussion.

    If we do end up corresponding further, though, please… call me Tom.

  • http://www.bottlesandmore.com Jim

    I am pretty sure that I have learned more about cork in the last 5 minutes than I knew my entire life. Great look at what cork is and where we are headed in the bottling business.

  • http://www,carone.ca anthony

    wow,
    I never would have imagined that an article on TCA and cork would ignite so easily like gasoline…

    I am surprised that none of the experts even once mentioned a highly probable cause for mis-interpreted cork-taint smells could be related to Geosmin.

    Not a word; but Geosmin has been the main problem in many vineyards for about 10 years now.
    It is also very much detectable by the human nose, unlike TCA or TCB.

  • http://reignofterroir.com Ken Payton

    @ Anthony, actually Tom mentions geosmin in a comment above. Regards.

  • http://www.carone.ca anthony

    OOPs. Sorry about that. Did not read thoroughly. Apologies Tom.

  • http://www.wallstreet-online.de/nachricht/3097640-eans-news-orbit-office-ag-unterbietet-deutsche-netzbetreiber-beim-sms-versand-ins-ausland

    Wow, hast du das gelesen? Geh mal auf Cortal Consors und gib mal die Orbit Office AG ein (WKN A0M6HN).Da hast du gleichzeitig die letzten Pressemitteilungen, die von heute ist wohl der Knaller! Da scheint was richtig grosses zu laufen, ist ja fast vergleichbar mit Freenet 2002-2003. Der Wert ihrer Aktie hat sich in wenigen Monaten verzehnfacht, irre! Und die Orbit Office scheint den Markt jetzt zu rocken so wie die damals. Die hatten in den letzten Tagen schon immer sechstellige Umsaetze, da braut sich was zusammen, muss ich bei sein, will auch mal absahnen! Schau auf Cortal Consors https://www.cortalconsors.de/Kurse-Maerkte/Snapshot?dont=delete&from=ax&id_name=ISIN&id=CH0035049490&type=STO

  • http://forexhandelssystem.wordpress.com/ Peter

    Heyhey, ich lese bereits schon häufiger auf deinem Blog mit und lese die Artikel mit großer Aufmerksamkeit. Sie gefallen mir sehr. Sie sind sehr anregend und sind gut neben dem Business zu lesen. Okay, das war erstmal das Lob. Dafür bekomme ich den RSS-Feed nicht in meinen Feedreader hinein, es kommt auch keine Fehlermeldung oder Ähnliches, es passiert einfach gar nichts. Ich probiere es Morgen einfach nochmal aus. Ich plane ein themenrelevantes Blog zu starten, meinst du das macht in dem Bereich überhaupt noch Sinn oder sollte ich mir lieber ein anderes Thema finden? Ist ja nicht ganz so einfach heute noch erfolgreich ein eigenes Blog zu pflegen und neue Besucher zu gewinnen. Was meinst du?