Why does wine often not taste right? The answer lies in a little-known chlorinated compound called TCA, which can taint corks and sometimes even entire wineries...
It is a feeling that many of us know only too well. We go to a restaurant. We order a bottle of good wine and wait for it to be brought to the table. The wine arrives. The waiter pours a little into our glasses. We try a sip. It doesn’t taste right. It’s not that it is too acidic or anything. But the white wine is a strange colour. It has no aroma. Instead, it tastes a little of wet cardboard.We look at the waiter. By now, we know the rules. When waiters ask us to taste wines they are not asking us whether we like them. They are asking us to check that the wine has not been ‘corked,’ or spoilt.
But is this wine corked? Is it meant to taste this way? We are not sure. We ask to see the sommelier or the manager. He appears at the table, tries the wine and looks curiously at us. The wine is fine, he says, what seems to be the problem?
We retreat in the face of his superior knowledge. Perhaps we just don’t like the wine we’ve been offered. Another member of our party offers to try the wine. It’s okay, he or she says reassuringly. And so we proceed with our meal, sipping at a wine that we’ve been told is fine but which we still think is not…
A couple of years ago I wrote in this column about the number of corked bottles I had encountered at Indian hotels and restaurants. Sanjay Menon, the luxuriantly whiskered wine importer who is an old friend, sent me an angry mail complaining about the piece. Yes, he conceded, corked wines were a problem. But the situation was nowhere near as bad as I had described. Further, he added, I had emboldened not very knowledgeable customers to return perfectly good bottles of wine. When sommeliers remonstrated with the customers, they referred them to Rude Food.
I have some sympathy with Sanjay’s position. But I stand by what I wrote. And now that I’ve read a book on the subject (To Cork Or Not to Cork by George Taber), I’m going to say it again. In fact, the problem is even worse than I realised. And I’ve only just worked out why.
When sommeliers concede that a bottle of wine is not fit to serve, they usually cite one of three reasons. The most common, in Indian conditions, is storage. Wine is a delicate liquid. If it lies out in the docks for weeks, without the benefit of a chilled container, while customs officers wait for the paperwork to be processed, it may well spoil. Besides, many hotels and restaurants do not store their wines properly. And even those who do store them well admit that they have no way of knowing how the wine was stored before it got to them.
I know of whole batches of French wine where I have not found a single bottle good enough to drink. Sommeliers apologise but say that it is a problem with the importer: the wine was probably in this condition when the restaurant received it.
The problem with storage is more common in India than in the West but oxidisation is a universal phenomenon. The relationship between wine and air is a tricky business. Expose a young wine to air (through aeration or decanting) and it takes on the character of an older wine with softer tannins. And the wine in your glass will change in the course of the evening as it comes into contact with air.But expose the wine to too much air and it will spoil. We all know the feeling. We open a bottle but cannot finish it. We recork the bottle and keep it overnight. By the next day, it is undrinkable.
Oxidisation is one major reason for wine spoilage. If you order wine by the glass at a restaurant, there is a distinct possibility that it will come from a bottle that was opened the previous day and the wine will taste foul. Some bars and restaurants try to get over this by using better quality wine-stoppers rather than re-sealing the wine with its own cork but this often fails.
Oxidisation can also happen in the bottle. Sometimes a cork shrinks in the neck of a bottle and air rushes in. The wine inside is spoilt but you don’t realise this till you open the bottle. One reason for this with old wine could be that if it is stored upright, rather than sideways with the liquid in constant contact with the cork, then the cork could get dry and shrink.
But often, even when wine is properly stored, the cork shrinks anyway. And sometimes when the bottle is stored upright, it makes no difference to the cork.
Nobody knows why this should be so. The problem is that corks are natural products, cut from trees and though they may be outwardly similar, a microscopic examination will reveal that no two corks are exactly the same – it’s rather like snowflakes.
There is a third problem and that is cork taint. For years (centuries even), the wine business has known that some corks seem to infect wine even if it is properly stored. But nobody can tell, merely by looking at a cork, whether it will taint the wine and make it taste of damp paper. So, the wine business goes ahead and uses corks anyway, privately admitting that up to five per cent of all corks will taint wines.
Five percent? That’s a pretty high figure, isn’t it? It’s like saying that of the last 20 wine bottles you opened, one was probably tainted. If Apple produced computers with a five per cent failure rate it would go out of business. If five per cent of the potatoes we buy were unfit to eat, we would create hell.
So why does the wine business get away with it? Well, mainly because all of us can tell a bad potato or a computer that doesn’t work. With wine, as we’ve seen, the situation is more complicated.
But why are corks tainted? And why is it that sometimes even when the corks are fine, a winery’s entire production can taste of wet cardboard?
The scientific answer to that question emerged in France as recently as the 1980s. But the French wine business contrived to try and talk as little about it as possible.
In 1981, French scientists who had been working on the causes of cork taint decided to use mass spectrometry – a technique that identifies the individual compounds in a mixture – to see if corked wines were chemically different. They found that all corked bottles contained a chlorinated compound called trichloranisole (TCA), while good bottles had no TCA.
They found that TCA could spoil wine even when it was present in very low quantities. A completely spoilt bottle of wine had only 100 parts TCA in a trillion. At 30 parts per trillion, most people can detect the familiar odour of TCA in a wine. And at 10 parts per trillion, most wine lovers or sommeliers can detect it. Real experts can tell it at even lower levels.
The conclusion of the French scientists was that TCA was so strong that it was the equivalent of putting two cubes of sugar into a large lake and having all the water turn sweet.
Many corks had been contaminated by TCA. Nobody was sure how but one view was that they had been infected on the tree itself. Another was that they had been washed in chlorine which led to the creation of TCA.
What was clear was this: the only way to tell if a cork had TCA was to measure it scientifically. The cork did not actually smell bad till it came into contact with the wine.
But even after these results were published, cork manufacturers refused to test their corks. And so, nearly every wine producer in the world used some proportion of tainted cork. So it was entirely possible that say, one bottle in a case of very expensive Mouton or Lafite was TCA tainted. But customers would only find out when they opened the bottle. And even then, sommeliers would deny that the wine was bad.
By the 1990s, things had got worse. Scientists were finding TCA in wine even when the corks were not infected. They searched deeper and found that the problem was in the wineries themselves. Chlorine-based compounds were used in wood preservatives. They turned up in porous plastics. Once they took on a gaseous form (with a molecular structure similar to TCA) they flew through the air like mystery viruses and infected air conditioning systems, barrels, floors, racks, hoses and virtually the entire winery. That’s why whole batches of wine ended up tasting corked when they were bottled.TCA affected nearly every wine in the world. The 1994 vintage of Chateau Latour had 360 parts of TCA per trillion! (remember, a bottle is completely spoilt at 100 parts!). Other Bordeaux big names were also found to contain high levels of TCA in tests conducted by the French magazine L’Express.
Fifteen years after TCA had been identified, the French finally called in scientists and asked them to clear their wineries of TCA. Even then, some wineries did not bother and few people talked about it publicly. And in other countries, wine makers remained largely ignorant about TCA.
California did not come to terms with the problem for a full decade after the French began their clean-up and cover-up operation. In 1993, the highly praised boutique winery Hanzell Vineyards found TCA contamination in its Chardonnay and Pinot Noir. The wine maker refused to accept there was anything wrong with the wine but the owners hired scientists who told them that their Pinot Noir had 3.2 parts TCA per trillion. This was not a high enough level for all laymen to detect it (they would just think that the wine was not very good) but wine lovers could tell.
Hanzell spent vast sums on a clean-up, found the source of TCA in the winery and offered to buy back any bottles of infected wine. Uncharacteristically, it also went public, breaking the wine industry’s conspiracy of silence.
And that is how TCA came to wider public attention. The TCA experience teaches us several things about the problems with storing wine and with detecting corked bottles.
n First of all, levels of spoilage are relative. Only an idiot would drink a bottle with say 20 parts TCA in a trillion. And most sommeliers would have to take that back, these days.
But what happens when the quantities are lower? Sommeliers have a term for it. I was once served a bottle of Puligny Montrachet by one of Sanjay Menon’s sommeliers. The wine was clearly off – knowing the science now, I would reckon that the TCA was probably 7 parts per trillion. But it wasn’t stinking and hadn’t turned into vinegar.
I told Sanjay’s sommelier (a nice Italian lady) that I knew the wine well and this bottle was clearly wrong. She tried the wine. The bottle was fine, she said. But it tastes wrong, I insisted.
Oh, that’s because the wine was not ‘showing well,’ she retorted. So that’s what they call low levels of TCA: not ‘showing well’.
Fortunately I was at Bombay’s Maratha where service standards are extremely high so they over-ruled Sanjay’s Italian sommelier and replaced the bottle.
Would other hotels have done it? Would they have done it for every guest? How many of us would have had the confidence to argue with a European sommelier? (I know that I nearly lost my nerve.)
* But this may explain why the wine tasting ritual can get complicated. I recently went out to dinner with a hotelier friend of mine who deals with wine professionally. We ordered a Sassicaia. My friend tried the wine, said he wasn’t sure but thought it was slightly corked. I passed it on to the best amateur wine taster I know who was also on our table. She tried the wine and thought it was fine.It was left to me to decide. I went with the professional’s judgement.
So, who was right? Both of them, I think. A wine being spoilt is not an absolute quality. Some of us may detect TCA better than others.
The only questions that remain are: when do you decide it’s worth sending it back? And when does a restaurant agree that a wine has too much TCA to serve?
Is 7 parts of TCA per trillion too much? Is 3 parts enough to return a wine? There are no absolute answers.
* While scientific analysis does not lie, the palate can be fooled. Research among wine drinkers has revealed that it is easier to detect TCA taint in white wine than in red.
It also more difficult to detect TCA in high alcohol wines than in low alcohol wines. So low-alcohol white wines like champagne are the quickest to be deemed corked or spoilt. Some years ago, there were innumerable complaints about cork taint with Cristal champagne.
* Since so many of these problems have to do with corks, why don’t more wines use screw tops?
Good question. On the whole, screw tops offer better protection against TCA taint. But the French still see them as too downmarket in image and many of us think that pulling the cork is part of the romance of wine.
* Can TCA taint affect all wines? Yes, absolutely.
Remember that California has only just begun cleaning up its act. Other countries have yet to start. The French checked their wineries in the late 1990s. But they don’t check their corks. So you could get TCA taint from an infected cork.
Some rules do apply though: (a) if it is a good wine from a country that uses a lot of screw tops (New Zealand, for instance) then the chances of a TCA taint are less because the screw top suggests that the winery is familiar with the TCA problem.
And (b) more expensive wines use more expensive corks. And cork manufacturers are more careful with expensive corks. So the chances of cork taint are a little lower, these days.* What about Indian wines? The honest answer is that I don’t know. We all say that too many bottles of Indian wine display massive inconsistencies. Many of them are spoilt by the time they get to the consumer.
We have always assumed that this is because of low quality control, exposure to heat or poor storage. I’m sure all these factors play a role.
But what about TCA? Do Indian wineries subject their wines to spectrometric analysis? Are they as choosy about their corks? I think we should be told.
* So finally, don’t feel bad about asking for a second opinion if you think a bottle doesn’t taste right. Do not be intimidated by sommeliers. And remember that most wine waiters and restaurant managers at Indian hotels know even less about TCA than even you and I do.
If you think it is spoilt, send the wine back. It’s as simple as that.