Three times it happened recently, in the space of just 10 days. That satisfying sound, thwug, as the cork is drawn. Nostrils twitching in anticipation as the first drop is poured. Then . . . Ugggh! Mouldy dankness. Mustiness mixed with a dash of dirty socks. You know, even before it crosses your lips, that you don't want to drink it - and you shouldn't. Back it goes to its supplier who should stump up another bottle. This one is corked.
It's strange to report that, even though modern, squeaky-clean winemaking practices have reduced the likelihood of a whole range of problems which can make wine taste awful (keep reading to get the grisly low-down on these), the incidence of cork taint is on the increase. That musty "off" smell is generally caused by the release of a chemical compound, trichloranisole (TCA), attributable to a mould growing in cork.
For reasons that are not entirely clear, sterilisation procedures in the cork processing industry have so far failed to halt TCA's onward gallop, despite pressure from severely disgruntled winemakers and a ton of research .
How many bottles are affected? With estimates varying between five and 10 per cent, this whole, corky business has generated heated debate and a certain amount of positive action. Oz Clarke is one of those who believes the higher figure is accurate and demands a pragmatic response. "Let's go for plastic corks as soon as the environmental problem of disposing of them in a suitable way has been solved," he said in Dublin last year. "The situation with traditional corks is crazy. It's simply unacceptable to have a product with a 10 per cent failure rate. That's like sending a whole batch of Ford Fiestas out of the factory without brakes!"
His views have been vigorously echoed, not just by other pundits but by winemakers and wine suppliers. Penfolds, part of Australia's mighty Southcorp group, is probably the biggest winery to have addressed the problems of cork taint on a broad front, funding research, stepping up quality control and experimenting with what are known in the business as "alternative closures" - synthetic stoppers and screw tops.
Hosting a winemaker's dinner at the Clarence Hotel last summer, Randall Grahm of Bonny Doon in California announced his defection to synthetics, producing out of his pocket a handful of examples - grey being favoured over an almost obscene looking flesh-pink bung. In his wake, Ed Flaherty, the American winemaker now working at Errazuriz in Chile, said he was urging the use of synthetic corks even for top-of-the-range bottlings.
"They definitely keep the wine much fresher." It's probably no coincidence that the Chilean winery Cono Sur - Flaherty's last employer - is already using synthetic stoppers, this time in smart black.
They are not alone. Whether we like it or not (and I must confess synthetic substances don't look or feel half as appealing to me as traditional cork), "alternative closures" are probably the way of the future, at least for inexpensive everyday wines. It seems likely that more supermarkets will follow the lead of Marks & Spencer who introduced synthetic corks five years ago and now have a new, improved version in over 10 per cent of their wines. Tesco/Quinnsworth is certainly moving in that direction. Even so, old-fashioned cork will continue to predominate - which means it's as well to be on the alert for those mouldy smells. The risk of cork taint is the main reason for the formal little restaurant ritual whereby the wine waiter pours a sample from a newly opened bottle and waits, somewhat tensely, for your pronouncement. Examining the cork is not, by the way, a reliable detection method. Nor have fragments of cork floating in the glass anything to do with a wine's drinkability. The smell of the wine itself is the giveaway, and in mild cases of contamination it may be difficult to judge with absolute certainty. A quick poll of wine waiters suggests that nine times out of 10, a wine rejected as corked is exactly that. The 10th time, a customer may just be showing off or trying to offload a disappointment.
Whether you're at home with plenty of time ponder, or in a restaurant and put on the spot, other wine faults may very occasionally emerge. Haziness is a bad sign, as are bubbles in a still wine - an indication of continuing fermentation. Oxidation is another problem, to be expected in old wines but not in youngish ones. Unintentional contact with too much air, either during the winemaking process or in storage, can result in a flat, flabby taste with fruit flavours very much subdued. Colour is often a useful pointer. An oxidised red wine will tend to be brownish, while a white one may be deepish gold. A vinegar smell may bolster your suspicions. Vinegar or nail polish remover aromas are an indication of volatile acidity (or VA, a buzz term much beloved of wine bores). This relates to a high level of acetic acid or ethyl acetate - not always a wine fault but unpleasant when extreme. While we're on the subject of nose-wrinkling odours, there are others you may encounter - caused by anything from simple hygiene to unfathomably complex chemistry. Sulphur dioxide, commonly used in winemaking as a disinfectant and preservative, can sometimes emerge in the finished product, producing the odour of a freshly struck match. Hydrogen sulphide, formed by yeast during fermentation, can get out of hand, leading to a Pandora's Box of pungent nastiness ranging from rotten eggs and burnt rubber to overstewed cabbage, wet dog hair or sweaty jockstraps. Pity the poor winemaker!
The latest thing I've learnt, in this fragrant field, is that insufficient use of sulphur dioxide may encourage the growth of a strain of yeast known as Brettanomyces (or chummy Brett for short). You'll know this is the case, the experts assure us, if your wine smells of mouse droppings or burnt beans.
A wet cardboard smell can be a sign of dirty filters. A sour, cheesy smell may mean dirty barrels. But maybe we shouldn't get too carried away on a Sherlock Holmesian mission to out badlymade wines. There really aren't that many. Besides which, a dodgy smell doesn't necessarily constitute damning evidence. After all, perfectly good Vouvray is often described as smelling of wet cardboard (or vomit), Shiraz is a reminder of sweaty saddles, Pinot Noir can conjure up both cabbage and manure, and Sauvignon Blanc has been compared with cat's pee. Personal chemistry has as much of a role to play as the big-scale stuff in the winery. The only sensible advice is this: If you like it, drink it.