Anyone who has bought wine in the last decade knows that you are as likely to find yourself pulling a synthetic cork, or even unfastening a screw-top, as you are to ‘pop the cork’ with an actual cork. Cork has been used for centuries as the stopper of choice for wine bottles because of its snug fit and air-tight qualities.
Although alternative stoppers are growing in popularity for a whole range of reasons, there are still steadfast proponents of the humble cork who argue that we are losing an important part of the wine experience when we ditch that small cylinder of porous wood for its plastic or tin competitors. The cork used to make wine stoppers comes from Mediterranean oak. The oaks have their bark removed and strips cut off, which are then allowed to dry for half a year. The strips are then briefly boiled before the stoppers are punched out. The corks are then sanitized and shipped to wineries.
History of Corking Wine
Although cork stoppers have been found in amphora dating back to the first century, the modern use of cork in the wine industry dates only to the 18th century, when cork began to be systematically cultivated and harvested for stoppers in Portugal and Spain. In the same century, Dom Perignon began to exclusively use cork in his champagne, and natural philosophers in England and Italy began to examine the chemical and physical properties of cork which made it such an ideal bottle stopper. The widespread transport of wine in trade and to the new world had made it more important than ever to seal wine effectively to prevent transported wine from turning into vinegar during shipping, and the resulting demand for cork stoppers kept the cork industry bustling.
So if cork is such an ideal seal for wine, why is the market for alternative stoppers so strong? The largest problem with natural cork is something called 2,4,6-trichloroanisole (TSA) or cork taint. This algae-related chemical compound can be produced by a variety of interactions, many of which involve airborne fungi and phenol compounds which can be found in various woods. The result is wine which is ‘corked’, leaving a harmless but unpleasant flavor. One in twenty bottle of wine may be affected by some level of cork taint, which explains why the wine industry is interested in ways to avoid this contamination.
The Emergence of Synthetic Cork
Synthetic plastic cork is not vulnerable to cork taint, and has grown in popularity for young wines. Consumers tend to accept synthetic cork as easily as we accept the use of synthetics in other areas of our lives. Wineries are not universally enthusiastic however, since the first few generations of synthetic cork have failed to be efficient enough to use in aging wines. Wines bottled with these corks tend to have a shorter shelf life because the synthetics degrade with time, compromising the seal.
Tin screw tops don’t have that problem—in fact, they seem ideal: inexpensive, long-lasting, and tightly air-proof. The controversy continues though; defenders of the traditional cork accuse these stoppers of being too efficient at preventing oxidization. This school of thought holds that wine needs a minute amount of oxygen exposure—not too much or too little—for full maturation and flavor development, and that natural cork allows exactly the proper amount of air to filter in through the minute pores of the stopper.