To cork or not to cork? That is the question. Let’s examine traditional corks, how they are manufactured and the problems that can occur, as well as other forms of wine-bottle closures.
The traditional cork is made from the bark of the cork oak (Quercus suber), a tree which mainly grows in Mediterranean countries. Growth is slow—very slow. In fact, it takes about 45 years to produce bark thick enough to cut bottle corks. Cork trees are harvested by carefully lifting or peeling lengths of bark. The cork should be kept intact as much as possible to make it easier to work with. Once the bark is peeled, it can be lifted every nine years.
The peeled barks are left out to dry in the forest for several months. When the barks are delivered to the factory, they are first immersed in boiling water for a couple of hours to kill off insects and micro–organisms, dissolve tannins, and increase the thickness and elasticity of the bark in order to make it easier to work on. After resting for one to two weeks, the cork may be boiled a second time. Sheets are sorted according to quality and thickness, and then cut into strips. Following the direction of the grain, the corks are punched out. This can be done by machine, or with hand-operated or semi-automatic tools. Best results are by hand as a person can select the best place to punch for quality. The waste cork parts are made into pressed corks.
After the punch, the corks are processed mechanically, the ends are cut to desired size and the body is smoothed. Then, a machine sorts the corks by visible pores on the surface, and then they are disinfected with bleach. The longer the cork is in contact with the bleach, the whiter the cork. Corks are then typically branded with the winery’s name and any other information needed. The final step is treatment of cork surface with silicon or paraffin, which allows for easier removal.
Corks are sold according to quality, from the pressed corks to best ones that have the least amount of pores. If you’re a top Bordeaux producer whose wine will last 40-plus years, you probably want the best corks.
So why all the fuss about corks and alternative closures? We have heard the term a wine is ‘corked’ used in conversation. This is when the cork has become tainted by the presence of bacteria. The bacteria grow and fester over time, which then taints the wine. It is not harmful to drink, but has an unpleasant musty smell like wet cardboard or dirty dishcloths. As a result, it changes the wine’s smell and taste so it no longer is the original wine.
Cork is a natural, living product and can be exposed to bacteria in its production, transportation and storage. This is an ongoing problem in the wine world, with an estimated 5 percent of corks becoming tainted. A cork can be slightly ‘corked’ or more obviously ‘full-blown.’ If you are not familiar with the wine and it is only slightly corked, one may assume the quality of the wine was not good, whereas the slight taint has not shown the wine at its best. Therefore, corked wines go by unnoticed by many consumers.
This is where alternative closures come in.
Stelvin screw caps
Long associated with cheap jug wine, these have a poor public image. However, several leading wineries, such as Penfolds and Hogue, have conducted tests comparing the different closures. In all studies, results have shown the screw cap to be the champion closure for ensuring quality and freshness of the wine. Hogue, which conducted a 30-month study on synthetic closures vs. natural cork, now uses screw caps for its annual 570,000-case production.
Screw caps, although better, lack the romance of the natural cork. Hopefully, the wine consumer becomes more accepting that screw caps are good, and should be used for more expensive bottles. New Zealand pushed this screw cap movement among its many wineries, which collectively decided to make the switch from natural. And now, wineries all over the world are embracing this practice.
Several other alternative closures have hit the market: synthetic corks, Zork, glass stoppers etc. to combat the taint problem of natural corks. All do a good job and some, like synthetic, are more suited to wines to be consumed within a few years.
So when buying wine, do not be shy of alternative closures, this is the winery’s effort to bring you their wine the way it should smell and taste.
Tasting Tip: Smell your wine first to detect any flaws suck as ‘corked’ wine. Then taste. A ‘corked’ wine will taste flat and musty, and would be lacking/devoid of fruit on aroma and taste.
Wine Recommendation: Thanksgiving is upon us, which means a wide selection of wines that work from Riesling and chardonnay to pinot noir and softer reds—the more, the merrier. Most of these wines will have a screw-cap choice, try them to ensure your wine is not ‘corked.’ Cheers!
Certified Sommelier Stanley Browne is the owner of Robust Wine Bar in Webster Groves, Downtown at the MX and in Edwardsville.