Can a whisky be corked? Is corked whisky a thing? Can you smell or taste cork taint in a high alcohol spirit like whisky? The answer is, unequivocally, yes. Let’s dig in….
It’s almost 20 years ago now that a whisky buddy and I attended a whisky masterclass in Sydney that has long stuck in my memory. The tasting was being hosted and presented by the brand owner and spokesman for a moderately-known Scottish independent bottler. The event was going well until someone in the audience, quite correctly, detected cork taint in one of the whiskies and raised it with the presenter. “No, not possible,” fired back the host, “whisky is immune from cork taint because the bugs can’t survive in the high alcohol”. My colleague and I looked at each other with a knowing nod and we promptly both walked out. (True story!) Our tolerance for whisky brand ambassadors who either don’t know their stuff or who simply lie to their audiences was always very low.
No one questions or queries cork taint in wine. Having said that, few people actually understand the science and chemistry behind it, but at least it’s not shrouded in myth. Cork taint in whisky, on the other hand, is still a very misunderstood area. It takes a bit of training, knowledge, and experience to identify cork taint – in wine or whisky – but before discussing that, let’s actually address what it is and what it is not.
Despite the name, cork taint is not a deteriorated cork, nor is it the result of a loose or crumbly cork. Also, despite the name, some “corked” wines and whiskies became contaminated not through or because of the cork but, rather, were infected by other materials that the liquid came into contact with during production, transport, or packaging. We’ll explore this more in just a moment.
Cork taint is not a bug or a bacteria, but it is the by-product of a bug. Specifically, it is a molecule known as 2,4,6 Trichloroanisole (more commonly referred to as TCA), and it’s produced when airborne natural fungi and bacteria come into contact with chlorinated phenolic compounds. These chlorinated phenolic compounds are found in wood preservatives and other chemicals (e.g. some pesticides, plus bleaching agents used in paper and cardboard production) and thus they can readily be present in many of the materials that are used in the production and packaging of whisky. For example, wooden pallets for storage and transport of casks and raw materials; paper and cardboard packaging; even the paper barriers used when chill-filtering spirit!
Cork has a high affinity for TCA, and the production methods & manufacturing processes involved in the cork industry are particularly prone to producing TCA and thus contaminating the corks. As such, cork is the usual suspect when a whisky is infected, but it is not always the culprit. More critically, TCA is highly infectious and it transfers easily through wood. A humble wooden pallet treated with the right (i.e. wrong!) preserver chemicals becomes a magnet for TCA, which will quickly transfer to the whisky casks sitting on the pallet, and – boom – the whisky inside is infected. Wooden-lined shipping containers can also carry TCA and so, whilst rare, even the completed, 12-bottle cases being shipped from Scotland to its overseas markets can potentially become contaminated simply whilst on the water.
The bugs (fungi and bacteria, don’t forget) that lead to the production of TCA – typically penicillium or aspergillus, but also botrytis cinerea and rhizobium – cannot survive in the high alcohol of whisky, but the chemical they produce, i.e. TCA, can happily survive. And once TCA is “in”, it’s in. This is also the reason why you can have corked wines and whiskies in bottles that don’t even have corks! Yes, it’s perfectly possible – and not uncommon – to encounter corked wine and whisky in bottles that have screw caps. Sadly, many restaurant and bar staff still need to be educated about this.
Knowing now where cork taint comes from, you’ll understand that it’s thus viable and present in other drinks and foods where the same risk factors come into play. Cheese and sake are two such examples. (Although good luck complaining to your waiter at a restaurant that your cheese is corked!)
The reason TCA is such a kicker is that it is perceptible and detectable at ridiculously low concentrations – as low as 5 parts per trillion! In wine and whisky, you’ll usually detect it on the nose. It typically presents as a mustiness, although bad cases will smell very distinctively of wet newspapers or wet cardboard. Wet dog and damp basements are also common descriptors.
In low doses, TCA robs a whisky of its lighter, more vibrant notes. It can make a whisky seem dull or flat, and you’d typically only identify this if you’re very familiar with the whisky and how it usually smells and tastes. Many drinkers write off a whisky thinking it’s just a bad batch or that the distiller has dropped their standards when, occasionally, TCA might actually be the culprit.
In higher doses, the whisky will smell of the descriptors outlined above, i.e. mustiness and wet cardboard. Experienced drinkers will almost always identify TCA on the nose – there is no need (and, usually, no desire!) to actually taste the whisky. The worst-affected whiskies are simply undrinkable.
The final aspect to discuss is how prevalent or common TCA is in whisky. Numerically, it’s less common than in wine, but that’s simple probability – there are far less bottles of whisky being produced than wine! For me, personally, in 25 years of hardcore whisky appreciation, I’ve encountered five bottles that were so badly affected by TCA, they could not be consumed. I’ve encountered a further eight or nine bottles or so that had TCA in lower concentrations which displayed that tell-tale mustiness and were grudgingly consumed – knowing the product was tainted. And I estimate I’ve probably opened upwards of ten bottles where the concentration of TCA was low enough not to reveal itself directly, but I suspected the whiskies were not shining as brightly as I knew they should have. I hasten to add that my experiences with TCA have been across many different brands and bottlings – there has not been a brand or bottling that has been a regular offender. However, I will state that the majority of TCA-affected whiskies I’ve encountered have been peated. Could this be because the presence of phenols in the malt and the chlorine in the sea air of Islay/Skye/Orkney increases the risk of the airborne fungi & bacteria encountering chlorinated phenolic compounds? I’ll leave that one to the scientists…
It is, however, notable when a complete batch of whiskies gets infected. A consignment of Highland Park 12yo came to Australia back in 2004 where clearly something common to all bottles either on the pallet or in the cardboard packaging, or perhaps the corks themselves had been tainted by TCA. Over a 12 month period across 2004 and 2005, I had whisky colleagues in Sydney, Melbourne, and Adelaide who all reported their encounters with an HP12 that was undrinkable due to its near-rancid notes of musty, dank, rotting cardboard. Similarly, there was a well documented case of mass contamination in the USA back in 2015 when a production run of Elmer T. Lee bourbon was affected by cork taint.
So what do you do if you encounter a bottle of whisky that reeks of TCA? You have three options:
i) Hold on to the bottle as a reference and use it as evidence to your doubting friends that you’ve encountered cork taint in whisky.
ii) Try and return the bottle to the store you purchased it from for a replacement. (Depending on the attitude and education of the store manager, this option will have mixed success). Alternatively, you could skip the store and try dealing directly with the distillery.
iii) A third option from left-field is to try and remove the TCA. We’ll leave the chemistry of it for another day, but due to the polarity and affinity of the respective molecules involved, it has been demonstrated that TCA will bind to polyethylene plastic. It is thus possible to remove TCA by soaking the whisky in a bowl with any form of polyethylene. Domestically, this means using products like Glad Wrap or Cling Film. The TCA will bind to the plastic, and you can then drain off the whisky for a much-improved dram. However, before you rush to your pantry, bear in mind that the polyethylene will also attract and strip out the spirit’s esters – and so, possibly, a self-defeating exercise.
So for the TLDR crowd who scrolled straight to the bottom, what are the take-homes from this?
1. Cork taint in whisky is not a myth.
2. Cork taint is not a bug and, yes, the chemical that causes it can happily exist in high-strength alcohol.
3. The source of cork taint in a whisky (that is, TCA) can get into a whisky not just via the cork, but via any number of materials or processes used at some point in the production, transport, or packaging of the whisky.
The taint is real.
Cheers,
AD
PS…if you enjoyed this article, you might also like our other “explainer” articles:
The complete guide to peat and peated whisky
The whisky lover’s complete guide to sherry
The complete guide to oak, casks, & whisky maturation
The 1980’s heavy metal guide to whisky
Oxidation – does whisky go off in the bottle?
The complete guide to non chill-filtered whisky
It is as well to remember that originally the term ‘cork taint’ in wine was due to ‘green’ cork and was relatively uncommon. Then sometime during the 1980s the natural treatment of raw cork, which of course is the bark of the cork oak tree, was deemed to take too long as, as up to that time, the sheets of bark were left exposed to the elements for more than eighteen months before processing into cut corks allowing the action of sun and time to dissipate the offending chemicals. Accelerating this process to weeks or just a few months involved initially ‘sterilising’ with chlorine based agents and of course this treatment was found to very much increase the perceived taint problem. Since that time other processes have toatally replaced the use of chlorine and the incidence of cork taint has once again dropped to a very low level but is unlikely to be totally eradicated wherever natural cork is used for reasons outlined in your article.
Okay so this doesn’t seem to exactly describe my issue but it’s a start I guess in trying to figure out the cause of the off taste I have been getting in whiskey within the past few years now. What I’m tasting doesn’t taste musty or like anything I would think of as wet cardboard. What I’m picking up on smells and tastes like VINYL, as in vinyl chloride; think cheap shower curtain smell and if you could literally translate that into a taste. I don’t know if any of you have ever owned a waterbed but the bladders of the oldschool waterbeds were all made of vinyl. And when the time came to move or sell the waterbed and the bladder had to be drained of its water, you could definitely pick up on the distinct smell of vinyl in the drained water. Now imagine that smell to your whiskey, and worse yet imagine the taste of it in your whiskey. That’s what I’ve been getting. It all started with a 1.75L bottle of Buffalo Trace in 2021 as I recall, which I have purchased several times before and enjoyed thoroughly without any issues. But that bottle was definitely tainted with a distinct nasty vinyl aftertaste and after-smell. I had contacted Sazerac and eventually they issued me a refund after returning the bottle and calling it “cork taint”. This did not seem possible to me at the time. I have my own speculations as to what may be causing this. Later I purchased a 1.75 L bottle of Weller which I had never tried, also by Sazerac. It did not have a cork but has a metal screw top. It had the same issue as the Trace, only worse. Mind you I have been drinking bourbons for years and never encountered this kind of off taste in any of them ever before just recently. Next I got another bad bottle with a similar disgusting stomach turning vinyl-like odor and aftertaste; a 1.75L (the size I usually buy) bottle of 1792 which I believe is also produced by Sazerac with the same problem to a very similar if not worse extent. I have dumped out several shots while trying to quaff others down (as with the Weller), but this bottle of 1792 remains partially full and I have at this point sworn off from consuming any more of it due to the issue. It now sits in my tainted liquors corner next to a 1.75L bottle of George Dickel #12 yellow label yellow cap that has a distinctly different unacceptable aftertaste like actual urine and makes me want to vomit from even attempting one shot of it (side issue). However I also have a random bottle of plantation brand rum that not only smells and tastes like vinyl but also burnt chemicals, plus a few bottles of bad wine. Unfortunately my newest bottle of bourbon has the same issue. It’s a bourbon I’ve had high hopes for though it’s the first time I’ve tried it; Woodford Reserve. It totally has a vinyl nose and mild vinyl aftertaste. Logic dictates deductive reasoning and common sense explanations. Since this never occurred prior to two three years ago and starting with a brand I had grown to appreciate and trust, expanding out to other brands thereafter, this seems to be possibly a growing industry wide issue. And what can cause a vinyl odor and taste? Occam’s Razor: The simplest explanation is usually/probably correct. My best guess is that the whiskey distillers somehow got sold some new equipment or methodology that incorporates some sort of uncured vinyl components in the sealing of their barrels, or their decanting equipment aka vinyl tubing being used to transfer the liquor out of barrels into holding tanks or directly into their bottles or seals in the holding tanks themselves, etc. This truly is the most logical and simplest possible explanation if you really think about it. There has to be vinyl contact somewhere. Not only is strong ethyl alcohol a natural solvent with which vinyl chloride is probably highly incompatible including plastisol (a form of vinyl used in seals and gaskets) but the natural extract from the wood barrels themselves may increase the possible reactivity and breakdown of the vinyl in direct contact even if that contact is seemingly only for a short duration. This is what I think has happened and has caused what I have been experiencing. Sadly at this point 100’s of thousands of liters possibly have been affected and it’s uncertain and unknown, at least to yours truly if the industry has even caught on to the fact that they may have really screwed up with whatever changes they recently made in this regard, even if seemingly slight and unintentional, that are now causing this. And I’m at my wits end. I’m about to swear of bourbon indefinitely because of this.. There’s only one brand left I have any faith in and if it goes the same way as the rest, I’m DONE. Whiskey and Rum, any and ALL liquors should have ZERO CONTACT WHATSOEVER with any VINYL containing plastic seals or tubing. PERIOD. No PVC piping either! Aka Poly-vinyl-chloride. Vinyl chloride monomer is some seriously nasty stuff and is toxic. There’s a reason they have banned it in play and chew toys for infants. Even if the quantity of dissolved vinyl alcohols in bourbons tainted with it is deemed “Below EPA Limits” of cause for concern, trust me, if you can taste it in there — no way that can be considered acceptable. And I CAN taste and smell it, or something that certainly mimics it to my senses. I have very refined senses and an extremely refined sense of taste and smell. I know that’s what it is I think I’m detecting. This that I’m detecting just cannot be cork taint; it seems to be vinyl contamination, quite obviously, and it needs to STOP. This issue needs to be corrected industry wide. No vinyl tubing may be used to transfer or decant whiskey into bottles. The lines must be made of stainless steel or copper? (which obviously costs more) or possibly silicone. Vinyl tubing and vinyl end cap (plastisol) seals in the ends or wooden aging barrels must be banned. They need to use the old fashioned type of seals as it has been done for centuries. No Compromise !!! Otherwise their are ruining an otherwise good beverage by tainting it with vinyl which must be 100% rejected by any and all whiskey connoisseurs and aficionados. This is a serious issue I’m bringing up. I just tried to search this on the internet and am seeing no results on this subject. The reason why is probably because it’s a brand new problem that has just recently arisen and no, my senses are not lying to me. So if anyone else has experienced the same thing, it’s not just you. Your senses are not lying to you. Stand up and speak out and and call and write the distilleries to complain. If they have been using plastisol seal in new barrels starting from some 3 to 8 years ago that are just coming to market, we may have a 4 to 8 year tainted whiskey period coming down the pike that we may all be stuck with from many of our favorite brands over the next several years. If this is the case I’ll probably just switch to cognac and/or brandies unless all brown aged liquors are going to be affected. If that’s the case I guess I wont be drinking anything but vodkas and gins for the next several years. You can bet that the industry is not going to want to fess up and admit to customers what has happened, because that would mean a huge drop in sales. No I presume they will just silently switch back to the original sealing technology and/or non-vinyl tubing once they figure out what has happened, if and/or when they figure it out. But honestly I really can hardly believe this has been allowed to happen. They sure made a huge mistake and gamble just to save a few bucks to try and make things “easier” and/or cheaper. Ending up with a tainted product is just absolutely not worth the risk and damage to your brand images and/or to the entire bourbon industry itself. To me this is very serious, because I happen to like drinking the stuff. So its a huge disappointment if I am forced to discontinue consumption because the interim quality of the products being released has dropped to unbearable standards and/or become tainted across the board. It’s just a major disappointment and with great regret that I am even having to write this extended comment/article on the subject. I think I better repost this to reddit. I’m about to have to contact Woodford Reserve and Sazerac again about this. From now on I’m just going to have to stick with my tried and true brand.
Hi Nick – very interesting (and detailed) observations. Also very unique…I’ve not heard comments or complaints along these lines in any other circles, although admittedly I’m more plugged into Scotch whispers, as opposed to bourbon whispers. There is, however, one unique parameter in your story: 1.75L bottles. That’s a fairly unique piece of info, and I daresay the vast majority of other bourbon drinkers who enjoy those same brands are consuming regular 700/750ml bottles. Have you purchased the same whiskies in smaller bottles and observed the same vinyl/plastic notes? If not, then I wonder if the phenomenon you’re observing is exclusive to something in the bottling process with those larger bottles?