Long practice of sealing wine has tainted past
Inevitably, I would write an article about wine corks. Hey, I am “The Cork Guy” after all.
A few years ago, one of my associates provided me a copy of George Taber’s book “To Cork or Not To Cork.” When presented with the book, I thought to myself: Is there enough about corks to produce a 276-page book? Turns out, there’s a lot to know about corks.
Since Robert Hooks first looked under a microscope in the 1600s, to the fabrication of synthetic corks, man has come to understand much about this phenomenal gift of nature.
Cork comes from the cork oak tree and is native to the Iberian Peninsula, which we know as the nations of Spain and Portugal. When bark ages, it transforms into cellulose material, which grows up to 2 inches thick every nine years and is harvested with no damage to the trees. So, as long as the tree lives, it will produce the cork to be harvested. The trees routinely live 150 years. One tree can produce in its lifetime more than 1 million corks. More than 90 percent of all cork used in the world comes from the two countries, with the highest quality coming from Portugal.
Since the late 1970s, there’s been a movement to produce a synthetic cork made from plastics to organics. The jury is still out on some of these attempts. They all have had their problems to some extent. Of course, the talk is all about screw caps as well, which also came under development at about the same time. The initial developments began in Europe and more specifically in France.
It was common up until the 1970s for a certain percentage of wine, which was bottled, to spoil or become “corked.” That happened to up to 2 percent of all bottled wine. This was caused usually by a defective cork being used or being sealed incorrectly, which would lead to oxidation of the wine. Much like an apple left out in the air after being cut, the fruit turns brown. Wine also becomes brown in color, woody in flavor and musty in odor, eventually spoiling completely to become vinegar. The word vinegar comes from the French vinigre, meaning spoiled wine.
Research by several universities and labs in the 1960s also identified a chemical that caused this effect in wine. That chemical — 2,4,6-trichloroanisole, more commonly known as TCA — is a chlorine-based product, which occurs naturally in cork. It was thought to be released as the cork began to disintegrate.
In the 1970s, a revolution was taking in place in Portugal as the monarchy was being ousted and replaced with a leftist regime. The new government was allowing peasants in the countryside to take over farms, including the cork forests. Before that, the oversight of the tree farms was at best haphazard, with a decline in the harvesting of quality cork and processing it correctly. Until the government corrected the situation, a lot of inferior cork came on the market. It would take five or more years for the results to show themselves. Consequently, 1986, 1987 and 1988 were the years of the tainted wines. Meanwhile, the use of chlorine to bleach the corks to improve their appearance increased TCA levels, tainting more wine. In some cases, complete harvests were ruined.
In the mid 1970s, wine consumption was rising in the New World, especially in North America and in Australia. The prosperity of the times drove up European wine prices, and the cash poured into the wine houses. Those houses, in turn, invested this new found wealth into expensive stainless steel vats and air-conditioned cellars to help stabilize and age the wine properly. Unknown to them, the wood they used to build these new buildings was treated with a wood preservative, which emitted the same TCA-based compound into the air, producing an odor similar to that of cat urine. This gas was absorbed into the juice as it fermented, causing the same problem as corking. In many cases, the buildings had to be treated to remove the chemicals. In the worst cases, the buildings had to be demolished and removed.
Independent labs arose during this period, offering assistance to the wineries in detecting TCA and other damaging compounds. By the 1990s, most of these problems were under control.
But the amazing growth of the industry required more and more cork and the quality degraded because of demand. The price of cork increased as much as 238 percent in a period because of demand. Substandard cork was passed onto the lesser producers or the New World wineries resulting in higher corking than usual. This is the main reason the Australians and North American wineries are, more than ever, turning to screw caps. It’s not that vintners scorn the tradition of using cork, but that synthetics more reliably deliver fresh, high quality products to consumers without spoilage or taint. So, to cork or not to cork? That’s the question as we go forward. But don’t be too hasty and throw away that corkscrew yet.
The Cork Guy
The Cork Guy is a local connoisseur of all things wine whose taste buds are especially adept at unraveling the mysteries of the vino world. We hope you will enjoy his visits to Coast Monthly. You can reach the Cork Guy at firstname.lastname@example.org