Corked wine in China: The fault with no name
Posted by admin at October 1st, 2008
By Frankie Zhao
-
The thing with corked wine in that Chinese consumers often don’t know it when they taste it.
I have attended big tastings, approached a table, realized the wine being served is corked, and seen only an inch of wine left in the bottle. This means a dozen or more people have already tried this faulty wine and yet it continues to be poured.
Another example: I once showed up late at a dinner and found people raving about a bottle of Chateau Lafite they were drinking. I took one sip and realized the wine was corked. I remained silent since they were enjoying the wine, but it reminded me again that many people do notice when wine is corked.
Some research finds people are much better at identifying a wine as very acidic or tannic than as corked. I have done work with Professor Ma Huiqin at China Agricultural University where we gave students faulty wines, including corked ones. We found that the wine characteristic they most easily identified was its weight or body. They also easily identified acidity. But, when it came to corked wine, it usually passed by their noses and tongues unnoticed.
Thus, in discussions of corks, screw tops, and so on in China, we need to realize that many consumers have little experience of what wine should taste like and, even if they noticed a wine is corked, they won’t necessarily identify it as a fault.
The link between corks and the spoilage agent TCA was established in the early 1980s. Producers of natural, oak-bark cork have been on the defensive ever since, especially in the early years, when a faulty cork was thought–erroneously, it turned out–to be the only way TCA could get into a bottle.
TCA (2-4-6 trichloroanisole) was identified as the culpable compound in many stinky wines by a Swiss chemist in 1982, and soon it was traced back to cork stoppers. The cork industry in Portugal and elsewhere initially tried to ignore the inconvenient truth, arguing that making the link public was libelous. Cork producers took refuge in the monopoly their product enjoyed–there was no other stopper in sight for fine wines, and anyway, most wine drinkers had no knowledge of the problem´s source.
Another spur for process improvement was the development of relatively simple, reliable testing methods. The combination of gas chromatography and mass spectrometry (GC-MS), utilizing solid-phase micro-extraction (SPME) to collect samples, has become an industry standard, able to detect lower and lower levels of TCA and related compounds and precursors.
The testing technique, combined with statistical sampling methods, was popularized in the industry. What GC-MS testing replaced was simple sensory analysis, which had relied on the notoriously uneven capacities of different people to sniff out trouble. The new, more objective, more sensitive technology allowed for testing at every step along the way in the cork production process, for weeding out bad lots early on, and for pinpointing where in the chain of production a problem of contamination might be occurring.
TP
This is a very interesting topic.
We have the same situation in Singapore as well. It can indeed be challenging to get the point across. But of course, when it come to wine matters, our Asian mentality usually hold us back, perhaps thinking we are not the experts in this hence our opinion might not be correct.
To boldly state that “the wine is corked” takes lot of courage,especially in restaurant settings in front of friends.
CHING
For someone with a little experience on wine drinking is somewhat weird that people don’t recognize a corked wine because to me it’s the most evident wine fault you can detect since the others (besides oxidation) are more subtle.
I agree with Frankie’s opinion. The main issue is that people are discovering wine and they might think that wine tastes like that, that maybe TCA is part of the wine’s profile.
But Frankie, you should have told those persons that the wine was corked… :)
Milton
Interesting topic, and especially interesting comment by TP about the scientific name of the known ‘cork taint’.
I would like to point, though, that not all considered corked wine can be traced to TCA. In fact, there are similar compounds such as TBA or TeCA that under sensorial analysis can be considered corked, but with a GC-MS analysis can reveal these other compounds that do not result on a bad cork but instead on conditions in the winery proper.
In another case, it is possible that even TCA may not be traced to the cork, but instead be traced to other contaminants present during the wine production. For example, the use of chlorines represents a huge risk for TCA contamination.
Therefore, do not so easily blame the cork, although the current term is ‘corked’. This should be considered in the mentioned closure debate.
And as a final note, nowadays cork producers are not taking a defensive posture anymore. Instead, at least the large ones are spending large amounts in R&D to study the problem and find ways to erradicate it.
Just to see the real size of the problem, the TCA noticeable level is of 3 ppt, or, in comparative ways, like a tea spoon with pure TCA tossed into a lake.
RD