How to tell if your bottle of wine is corked.

Apparently, the average, regular wine drinker (how regular, ‘regular’ is, I’m not so sure) will open approximately 100 bottles of corked wine in their lifetime. Imagine now, that by some freak of misfortune you happened to drink all of those 100 bottles at restaurants, each one accompanied by a suitably marked-up price tag, and you’re suddenly looking at a rather expensive future of miserable, unpleasant drinking. With this in mind, it seems a good idea to understand exactly what a ‘corked’ wine is, what it tastes like, and, most importantly, when to send it back.

‘Corked’ is an industry term that gets flung about a lot, and yet very few people actually seem to be able to explain precisely what it is. Wine can suffer from a number of faults, from factors imparted during the winemaking process (think dirty tanks and dodgy ferments), to issues resulting from packaging, storage and transportation.

Cork taint is generally a consequence of the latter, and is derived, as you may have guessed, from contaminated cork. It is not, as some people say, flavours imparted by those little bits of cork you sometimes find floating in your glass (this is generally caused by poor/over-zealous bottle opening skills), or indeed, by any particular amount of direct contact between the wine and cork at all – wine does not take on a ‘cork taste’ via simple cork contact.

Instead, cork taint occurs when the cork in question has been contaminated by certain airborne fungi reacting with chlorophenol compounds within the cork itself, producing a chemical called 2,4,6-trichloanisole (TCA). This chemical, even when present in only miniscule quantities, is responsible for causing the mouldy, damp-like aromas that are typically associated with corked wine.

The chlorophenol compounds that form the base of the reaction can infect the cork material at a number of points during the production process; as an ingredient of the pesticides sprayed upon the original cork trees, or as a side effect of sterilisation procedures undertaken, ironically, to kill unwanted microbial compounds. Mere nanograms is enough to turn a wine vile – a teaspoon, apparently, could turn a whole lake (following, I assume, plenty of rigorous stirring) – but however it’s formed and in whatever quantities, it smells and tastes truly foul.

But how to identify it? Foulness is not quite enough. Some wines, naming none in particular, do just taste horrid, and then there are the myriad other possible wine faults to consider. The prime indicator of cork taint is its distinctive smell, often described as being reminiscent of ‘wet-newspaper’, ‘wet dog’, or just a general, pungent aroma of stale, musty decay.

Such smells are harder to identify in a red wine than a white wine, due of course to the typical, associated taste profiles of the two styles, but another, perhaps less obvious indicator of TCA contamination is the numbing effects it has on the wines other, native smells. Some wine faults, such as maderisation (caused by excessive heat and oxidisation) or the presence of particularly large numbers of Brettanomyces (an especially potent strain of yeast), can be detected noticeably on the nose of the wine, but do not necessarily smother the original, more tasteful aromas and flavours.

TCA, on the other hand, tends to mute the base, anticipated character of the wine, concealing those strawberry and blackberry notes beneath a fuggy blanket of unwashed wet dogs. To put it simply; if the wine smells bad and is not what you expected, it probably has cork taint.

Needless to say, if a wine doesn’t have a cork, it doesn’t get corked, and thus the obvious defence against cork taint is to not use cork at all. This fairly robust approach has been adopted en masse by the nations of the New World, most notably in wines from New Zealand and Australia, where screw caps are the sealing method of choice.

Screw caps contain a liner on the underside of the lid that seals the bottle and prevents almost all contact between the contents and outside environment – a solution that certainly mitigates the potential for external contamination, but also inhibits the beneficial effects of gradual oxidisation that are so crucial for developing the taste profile of aged, bottle maturing wines.

Screw caps that do allow a small level of oxygen ingress have been developed, but it is widely considered to be too soon to accurately discern the long-term effects that screw caps have on ageing wine. Plastic corks, another sealing solution, both often fail to provide a secure, airtight fit and have been known to impart a rubbery, plastic-like flavour after extended periods of wine contact.

Glass stoppers, increasingly seen atop more artisan, boutique style wines, act as an effective seal, but once again almost completely inhibit any oxidisation. Cork then, seems destined to be around for a while yet. Advances in sterilisation techniques (using peroxide bleaching rather than chlorine based agents) have somewhat reduced the prevalence of corked wine in the industry, but eradicating the problem altogether currently seems impossible.

In the meantime, it is down to the consumer to know when they can get their money back. Unless the bottle in question is a particularly rare, expensive or similarly ‘one-off’ item, then it is certainly not unreasonable to request a replacement, and if no replacement is to be had, then to receive the money back – if a merchant or restaurant is unwilling to refund you, then they ultimately don’t deserve your custom.

But despite all the boo-hoos and the pitfalls, corks have a certain elegance, an historic class that any substitute would be hard to replace. There’s something immensely satisfying about the slick, slim foil, the twist of a corkscrew, the leverage, the soft pop as it’s pulled from the neck. It’ll be a long time before we see the back of them. The best we can do in the meantime, is enjoy the ride, shrug our shoulders, and think of the 100 other bottles we enjoyed that were just as good as we’d hoped.

Christian Lowe