Here’s another useful article giving background about metals in alcoholic beverages:
http://cat.inist.fr/?aModele=afficheN&cpsidt=20801948" onclick="window.open(this.href);return false;
Initial question :
At GJE, we have an average of 8 % corked bottles. Quite a problem when you check the average value of the bottles we served.
This BB is quite professionnal : mama Mia !!!
Okay, enough with the insults, Francois!!
![[berserker.gif]](/uploads/db3686/original/2X/8/8600bbd4810d342b8fbd4ffb62b4f0026275fd37.gif "berserker"){kind=small}
I’m pretty sensitive, but to be honest, generally run at about 2-3% actually “corked”, plus maybe another percent or so where I think something’s off but would rather not jump the gun. I agree with an above statement that heat damage contributes to “corked” judgements. So too does mild oxidation (flat nose), or even very mild brett - something a bit fungal and funky, hmm, might be TCA - but if you’re astute you’ll be able to spot the difference.
I very rarely finded corked wines, and I have a reputation of being sensitive to it. I have been to plenty of tastings where I think that people try to overcall TCA. But 1% sounds about right to me.
Some additional website hits re: “methyl mercaptan” “screw caps” wine:
Defending screwcaps" onclick="window.open(this.href);return false;
Jamie Goode, 19th January 2007
http://www.corkqc.com/currentresearch/Micro-Oxidation/SulfideReportWeb.pdf" onclick="window.open(this.href);return false;
CQC Internal Report
Sulfide Analysis of Screw Cap Wines 2/26/07
Some thoughts on bottle variation | STEVE HEIMOFF BLOG" onclick="window.open(this.href);return false;
Some thoughts on bottle variation, by Steve Heimoff where Clark Smith says:
July 21st, 2009 at 12:22 am
A few facts about lightstruck wine. First of all, the cause is light energy activating riboflavin as a reducing agent, and causing in white wines a cascade reducing reaction which is quenched in reds before it gets going, but in whites quite quickly (five minutes is enough in bright sunlight)produces a mix of sulfide compounds, mostly familiar like H2S (rotten eggs), ethyl mercaptan (diesel or onion), and diethyl mercaptan (canned asparagus), but also some exotic ones like ethyl methyl mercaptan, which smells like wet wool, almost a mothball odor and quite different from TCA.
Many dark bottles don’t offer much UV protection — it takes a special UV coating which much cheap glass is less likely to use in these days of Chinese imports.
It is extremely rare that a shipment of wine is lightstruck. It usually happens on the retail shelf or after purchase.
In my view, the most important sources of bottle variation are environmental influences of light and heat. Given perfect handling and storage, however, the cork closure is the main culprit.
Still, the way a wine is perceived in reaction to the environment in which it is serve — not just the food but the music, the mood, the lighting, the background aromas — have much to do with creating an harmonious experience or a dissonant one in which the wine shows us its best, and these influences are almost never discussed.
That does not mean we should taste and judge wines ganged into groups in the sterile environment of current vogue. Nothing could be further from the consumer experience.
Here’s a remarkable slide show on Reduction in wine in relation with post bottling evolution. Influence of closures and of some winemaking aspects, by Pascal Chatonnet (world authority on halogenated anisoles like TCA):
http://www.labexcell.com/dynsite/images/stories/conferences/UK_LONDON_AMORIM_2009.pdf" onclick="window.open(this.href);return false;
Chatonnet’s conclusion:
Don’t try to manage the risk of post-bottling “negative reductive evolution” increasing the oxidative status of the wine, or worst, treating it with Copper ! > But prevent any bad evolution by appropriate viticultural and wine making practices … > and choice of closure> .
Hi Mitch,
Thanks for posting the links to these articles and slide shows. I really liked the piece by Jamie Goode, which seemed to essentially argue semantics over terms such as “sulphidisation” and “breathing”, while not addressing the point that natural and synthetic corks allow some percentage of oxygen ingress that studies seem to indicate keeps post-bottling reduction at bay, while the vast majority of screwcaps as they are used now create anaerobic seals that seem to lead to a significant percentage of wines damaged by reduction. I noticed that he was at pains to emphasize that consumers are unlikely to spot wines flawed by reduction under SC, as he states that he has “tasted a number of wines with what I suspect to be screwcap reduction, and it’s not as noticeable as cork taint… I doubt any consumers will spot it unless they are coached.” Are we to imply from this statement that Mr. Goode’s conclusion that it is not a real problem worthy of concern if the consumer cannot notice it. I also liked Mr. Goode’s oblique endorsement of copper fining in the sentence: “In the reduced environment of a wine sealed by screwcap you’d be unlikely to see eggy hydrogen sulphide, unless the winemaker was negligent to bottle an already reduced wine this way.”
Glaringly missing from his article was that the IWC tasting was primarily of young wines, and that the incidence of sulfur-derived off odors (SLO) grows with time in the bottle- would love to see what the percentages would be of SLO-tainted wines if they were tasting four or five year-old wines sealed under SC- one might be a bit more likely to “to see eggy hydrogen sulphide” taint in the wines with sufficient bottle age. Also noticed he did not want to go into the nasty topic of heavy metal residue in wines sealed under screwcap that had been properly prepared by non-“negligent winemakers.”
Also was very interesting to see from Monsieur Chatonnet’s presentation, that cork-tainted wines appearing in their samples are down under 2% in 2006, 2007 and 2008. Again, I assume that these are just recently bottled wines destined for imminent release that are being tested by M. Chatonnet’s firm. Would be very curious to hear from Francois what the average age of the bottles that they are serving at GJE, where there, 8% TCA-tainted rates are currently holding. My gut instinct would be that these are slightly older wines and would be a pretty accurate reflection of the rates for TCA taint in top of the line corks a decade or so ago.
Best,
John
Forgive the slight tangent, but I wonder how much copper in wine can be attributed to the near ubiquitous use of the substance in vineyards, even (perhaps especially) by those domaines utilizing organic or biodynamic regimes?
Is there any data that breaks down the likely contributions?
Bob, I know what you mean, I go to some tastings where it seems people call TCA well before the wine has had a chance to even be smelled by or tasted by the rest of us. A lot of times they are right on, but oftentimes it is a bit of the Boy who Cried Wolf effect at play…
For me personally, I reviewed my last 600 non-screw-capped tasting notes, and found instances of 17 TCA-tainted bottles (with 2 more where others I was tasting with were sure the wine was corked but I could not concur). So, depending on how you count those two my rate is running 2.8% to 3.2% this year–with wines from all parts of the world and a fairly wide range of ages. I truly wish it was < 1%…
-Michael
Thanks for the semi-endorsement, John. It’s a complicated topic, and I’ve tried to achieve some balance in writing about it. It’s also a highly emotive topic in Australia and New Zealand, so it’s difficult to retain perspective.
Look, I know, and have written about, the post-bottling wine chemistry issues with low ox-trans closures. They’re real. But I’ve also had many brilliant Aussie wines that have been sealed by tin-lined screwcap. I know many brilliant winemakers who are happy with this closure. It would be wrong to suggest that the tin-lined screwcap is ruining all wines.
It’s very hard to write these pieces without upsetting people on both sides of the debate.
And the Chatonnet presentation? The first 14 pages are lifted from a powerpoint presentation I gave in France and Denmark last year! I thought they looked familiar.
A genuine welcome to the board Jamie Goode !
Hi Jamie,
Thanks for popping in and I appreciate very much the difficulty of trying to take a balanced approach to a subject that can stir up such strong passions on either side of the discussion. For example, to Mr. Starr I am a “bigot and lazy journalist” because I even dared to broach the subject in a questioning manner, and I am sure that there are several more pithy monikers for me that do not appear in print 
But as you noted in your post, there are some very real issues regarding post-bottling reduction for wines sealed in an anaerobic manner, as is the case with tin-lined SC as it exists today, and as the issue has evolved, it seems to me that there are two main issues revolving around this: 1.) Whether or not the incidence of wines damaged by reduction is equal or greater to wines damaged by TCA taint and other problems associated with the natural cork that SC were supposed to be an improvement upon; and 2.) Are there potential public health risks to the growing incidence of winemakers resorting to copper fining to “properly prepare” their wines for bottling under SC?
On the first point, I agree with your point whole-heartedly that reduction issues in bottled wine are much less easy for anyone to spot if they do not know what they are looking for, as the first signs of reduction problems generally occur on the palate, rather than on the nose IME- popping up as short finishes, metallic minerality and pinched fruit tones. And like many consumers, until it was pointed out to me that these are reduction issues, I simply wrote the wine off as being poorly made- period. This is the one issue that I think that winemakers and winery principals have not taken into account with regards to SC and reduction- consumers and merchants may not know that these characteristics are brought about by reduction, but they do notice them in the wine and conclude that the wine is flawed in some manner or that they simply do not like it. So they may not return the bottle to their grocer, but they will most emphatically not pick it up again on their next shopping trip. And this type of market damage can snowball dramatically beyond the one wine in question to hurt reputations of wineries, brands and even entire regions in the minds of consumers.
Now I have never said that post-bottling reduction issues afflict all wines sealed under screwcap- in my own experience with young wines my numbers run somewhere around twenty percent (but the vast majority of samples I am tasting are sealed under cork or synthetics, so I have no real sense of how my numbers stack up with those who are tasting far larger numbers of SC-sealed young wines)- so your point about many wines aging gracefully under SC is well-taken and I have no doubt that this is indeed the case. The question to my mind is whether or not there are a higher percentage of wines aging gracefully under SC today than there are under natural cork or synthetics, as this was once the crux of the debate between the various closures. Based on the numbers that I have seen for each closure (and I have read a ridiculous amount of research in this matter- fully understanding the potential for bias, given that each closure has its advocates and will interpret the data as favorably as possible in the direction of the author’s particular favorite), it certainly seems to me that there are lower percentages of wines damaged by their closure under natural cork than either synthetics or SC today (this was probably not the case ten years ago, but it seems pretty clear that this is the case today.)
2.) On the second point, the evidence very strongly suggests that copper fining is up dramatically with wines destined to be sealed under screwcap- several AWRI papers make this quite clear- and without the re-establishment of maximum levels and systematic testing for residual copper in wine by FSANZ, there must be a very real concern on the part of consumers, importers and governmental food safety agencies in the export markets as to the safety of wines bottled after copper fining. Without testing and max levels, there is simply no way to ascertain how safe the wines are for consumption. Here in the states we have a long history of industry self-policing itself in places like Love Canal- poisoned beyond repair by negligent industry- and it is not a very pretty history.
Certainly copper fining has been used as a method of last resort for decades to try and salvage wines that are reduced prior to bottling, but it is the incidence and dramatically larger scale on which this is being practiced today that is of concern- particularly since copper fining in the old days was done under the auspices of the old maximum levels on copper in wine. And the aggressive spread of copper fining as a matter of routine for wines to be sealed under SC is now leading to more blue fining with potassium ferrocyanide to try and get out the excess copper from the pre-bottling treatments, and as Geoff Cowey made quite clear in his recent AWRI paper, if this is not done with extreme precision, there is the potential danger of liberating cyanide from the fining agent and leaving this in the wine. To the average consumer or even to the researcher who has taken the time to wrangle with all of the technical papers on this subject, this just does not sound good and does not on its surface seem to be the most promising path to go down.
Lest we lose sight of the fact that this whole thing started ten years ago as a search for an improved closure over natural cork, whose track record at that time was pretty piss poor. As cork manufacturers will tell you openly, they did a lousy job of quality control and they are very well aware of the anger and resentment that they spawned through their inattention to the very serious issues of TCA contamination of their products at unacceptably high levels. As one of our winemakers so concisely pointed out earlier in this thread “it hurts to watch two years’ worth of work go down the drain because of your closure.” But one has to also realize that the cork industry has finally gotten “true religion” on TCA, and the cork products of today are not the same as a decade ago, with far greater quality control and dramatically lower incidence of TCA taint. They have strong research teams and labs, and there is little doubt that TCA will continue to diminish as a problem for natural cork as we move into the future.
On the other hand, we have SC, which has not proven to be the panacea that it was originally made out to be by its manufacterers. It was supposed to be “the perfect closure”- period. We now know that this is overwhelmingly not the case. Now I am not a winemaker or winery principal, but it seems to me that if the closure previously selected (to a certain degree based on the promises made by the manufacturer out of the blocks) is not performing up to standard, why not just change the closure again? Sure, corks cost a bit more than SC, and the investment in the machine to put SC on the bottles would be wasted, but this has to be weighed against the potential problems caused by continuing down the SC path when it has proven problematical and requiring tremendous manipulations of the wines pre-bottling (copper and blue finings) simply to make them potentially longer-lived under the closure. Does it really make sense on any level to continue to add heavy metals to wine simply to hang onto a closure that is not performing as well as advertised- rather than switching back to another closure whose own performance has skyrocketed up in the last decade, and where no additions of heavy metals to the wines pre-bottling are required? Or worse, to potentially add cyanide to the wine to get the copper out that had to be added only to use the SC? On the surface, it would seem to me that the answer as to which way to go would be self-evident.
Best Regards,
John
Thank you for providing a helpful perspective about the SC cork dialog, John Gilman. Since you have delved deeply into this topic, I’d like to draw your attention to an easily overlooked (under-appreciated, if true?) statement in the “critical review” I previously cited. How accurate the following quote on page 675 is I simply don’t know:
Potassium hexacyanoferrate (II) binds some metals and sulfides present in alcoholic beverages, > although it cannot be used in applications where Cu [i.e., copper] content exceeds that of Fe [i.e., iron]; > besides it may release poisonous HCN.
Emphasis added
Edit: I updated the link as the original no longer seemed to work.
OK, how about this:
some thinking out loud about closure choice. In some ways, it’s a question of managing risk. There are a range of trade-offs, because there is no perfect closure at present.
But how do we attempt to quantify this risk? Let’s have a go.
Natural cork
3% (may be lower, may be higher) risk of 100% loss of quality through cork taint
5% (estimate?) risk of 20% loss of quality after 10 years for corks that have a higher level of oxygen transmission
10% (estimate?) risk of 10% loss of quality after 10 years for corks that have a moderate level of oxygen transmission
Synthetic cork
100% risk of 10% loss of quality through flavour scalping of terpenic white varieties (Riesling, Gewurztraminer etc.)
100% risk of 5% loss of quality through flavour scalping for other whites
100% risk of 2% loss of quality through flavour scalping of reds
100% risk of 10% loss of quality after two years for white wines through high oxygen transmission of closure
100% risk of 10% loss of quality after three years for red wines (ox trans)
100% risk of 50% loss of quality for all wines after 3 years (ox trans)
100% risk of 70% loss of quality after 4 years (ox trans)
100% risk of 100% loss of quality after 10 years (ox trans)
Screwcap
2% risk of 30% loss of quality through post-bottling reduction
50% risk of 5% loss of quality through very low level post-bottling reduction
100% risk of 2% loss of quality for red wines (this is controversial, but often they just don’t seem to taste as good as the best cork-sealed bottles; a marginal thing, hence 2%)
Diam
10% risk of 50% loss of quality after 10 years in bottle (but this really is unquantifiable at present, and reflects the fact that while Diam seems stable enough so far, we aren’t sure whether they’ll be fine after 15 years in bottle, or 20 - although there’s no reason to suspect that they shouldn’t be)
Vino-Lok
10% risk of 50% loss of quality after 10 years in bottle (same as for Diam - long term performance is currently unknown - I’d like to see ox-trans data)
Hi Jamie,
Sorry for the delay in getting back to your post, but have been out of commission with a nasty flu virus and am just getting my feet back under me. I like your attempt to quantify the issues involved facing winemakers trying to decide which closure to utilize, but I have a hard time really grasping a comprehension of them without having some idea on what data you are using to base these numbers. In particular, when looking at the numbers you estimate for loss of quality in wines selaed with natural corks due to greater than desired oxygen transmission rates, I would be curious to know what you base your estimates on. Your numbers look likely to be based on the now widely discredited “dry cork” MOCON studies that have been shown to be methodologically flawed when discussing natural cork as a closure in the one hundred percent humidity conditions applicable to wine. I did not know if you were aware that these studies have been shown to be greatly wanting in applicability to the point in question, if these were indeed contributing to your estimates.
With your screwcap estimates, they look a bit optimistic and relatively subjective to me- do you have any data from studies that would support these numbers? I have had plenty of post-bottling reduced wines sealed under SC that I would rank as vastly above a 30% loss in quality due to sulfur-related odors and greatly diminished palate character. I do find it surprising that it is your impression that fully fifty percent of wines bottled under screwcap are flawed. But again, without reviewing some of the data upon which you based your estimates, it is really hard to comment intelligently about your attempts to try and quantify the issue. I have looked through what I have in my files and I cannot find any possible studies that would aid you in deriving the numbers here. If you could point me in the right direction, I would dearly love to become acquainted with this research.
But your broader point in that there are a myriad of considerations to be pondered by the winemaker before deciding on a particular closure is very well-taken, and I think that trying to build a matrix (as you have admirably begun here) could prove to be a very useful tool. I just attended a tasting where we had TCA-tainted bottles of 1985 and 1978 Corton-Charlemagne from Bonneau du Martray, and losing great old wines after twenty-five or thirty years of bottle age is no fun by any measure. But I would still suggest that much of the decision-making being taken today by winemakers remains based on exagerated claims on the part of SC manufacturers and faulty early studies done, and one of the most daunting challenges for any winemaker these days is to separate the current data from the discredited studies that seem to keep getting recycled in some circles that seem more interested in protecting a market share than protecting the wines from spoilage and the consumers from potentially unhealthy winemaking practices.
All the best,
John
Robert Parker recently tossed out a figure that seems in line with your original line of discussion.
http://catavino.net/wine/the-grand-garnacha-tasting-of-robert-parker-%e2%80%93-wine-future-conference/" onclick="window.open(this.href);return false;
“Two wines were double decanted for the event due to the detection of some unwanted post fermentation aromatics, but the aeration removed the problem. The natural cork closure was another hero of the evening as less than 1% of the 600 bottles opened for the tasting were tainted.”
Any guess which of the wines and under what closures needed to be double decanted? I’m assuming this was for low level sulphide reduction because it blew off eventually with airing? My guess is two of these four, assuming some are under screw cap.
Australia
15. Killikanoon Duke 2006
16. Greenock Creek Cornerstone 2006
17. Clarendon Hills Old Vines Romas 2006
18. Torbreck Les Amis 2005
A very big welcome to the board, Paul White.
Here’s hoping that you might find time and have an inclination to post again, every now and then! Several of us here have been following your insightful articles published elsewhere.
Mitch Smith
No, Parker made no such comment. That statement was written by the blog author, Raymond Magourty. Parker may have been at the event, but I’d be surprised if he tasted all 600 bottles personally.
Any guess which of the wines and under what closures needed to be double decanted? I’m assuming this was for low level sulphide reduction because it blew off eventually with airing? My guess is two of these four, assuming some are under screw cap.
Two guesses and two assumptions. Promising, especially from a journalist. The assumptions fit with your known prejudices. And the guesses are random. The fault is as likely to be brett as reduction. None of the four Australian wines listed are sealed with screwcaps - all are closed with natural cork.
Here’s hoping if you post again, you’re inclined to post something factually accurate.
Graeme
20% huh?
Sounds just like what you said at Dr Vino:
“But beyond my rant on whether or not all these “treatments” (rather an Orwellian use of the word) that the Aussies put their wines through are safe, there is little doubt that copper finings and the like do strip out much of the character of the wines, and are still completely ineffectual and simply put off the day when the wines go into permanent reduction under screwcap and are ruined. How do you make a screwcap-sealed wine taste and smell like rotting cabbage or burning rubber- put it in the cellar for a few years. They almost all get there over time.”
Screwcaps, scores, riesling, the Loire, Cali cab: John Gilman part two - Dr Vino's wine blog Dr Vino's wine blog" onclick="window.open(this.href);return false;
About 20%… almost all… no difference really.