Do you ever wonder where corks come from or why we use them? Do synthetic corks work just as well as natural ones? And what about those screw tops? Are they just for Two Buck Chuck?
Natural cork makes a great stopper for wine because it’s water tight, but still lets tiny amounts of air in. The cork comes from the bark of the cork oak, which is native to southwestern Europe and northwestern Africa. Cork is a sustainable product. The trees do not have to be cut down, and the cork grows back! Unfortunately, it is not a super-fast process. They don’t strip off the cork bark until the tree is between 15 and 20 years old. After that they have to wait nine or ten years before taking more cork bark from that same tree. The harvested cork bark is removed from the forests, and left out in the open air for six months before any wine stoppers can be made. Only high quality cork can be used as wine closures. The lower grade cork and crumbled cork is used to make a composite cork, like what is used for sparkling wine bottles. In addition, cork is used in many other products – anything from shoes to flooring and building insulation. With over 30 billion (yes, billion with a “b”) bottles of wine being produced every year, someone thought they would run out so they had to come up with an alternative to natural cork. Fortunately, it turns out there are more than enough cork oaks to keep pairing them with our wine bottles for at least another 100 years. It could be that “cork shortage” rumor was started by screw cap and synthetic cork manufacturers.
Synthetic corks are made from plastic and silicone compounds to look and “pop” like natural corks. They have two advantages. The first advantage is that they are cheaper than natural cork. This advantage is mostly for the wine bottler. The second advantage is that they don’t have that pesky “cork taint” that natural cork can have that contaminates an average of 5% of aged bottles. This can occur in natural cork when a chemical compound, TCA (trichloroanisole) transforms the wine into something nasty and undrinkable. With those two advantages come several disadvantages. First of all, natural corks maintain a consistent tight seal because they expand and contract with the glass. Synthetics do not. Second, synthetic corks do not “breath” to allow the small amount of oxygen in that helps to age the wine. On the flip side of that, if the synthetic cork doesn’t fit well, it may let in too much oxygen, leading to that not-so-lovely vinegar flavor. Finally, synthetic corks can be difficult to remove, especially if they’ve been in the bottle for 18 months or more. Having a wrestling match with the wine bottle can definitely sour the mood.
And what about those screw caps? One would think that the screw cap would be free of that undesirable TCA – cork taint. T’aint so. They are actually susceptible to the sort of moldy, icky aromas typically associated with contaminated corks. Screw caps have been around since the 1950’s, but were generally associated with very low end wines. That was, until winemakers in Australia and New Zealand started using them for some of their better wines. The screw cap is now the preferred seal of some winemakers, mostly for crisp whites or reds that are meant to be imbibed while young. (The wine, not the imbiber). They provide a solid seal, they have been designed to allow no oxygen to varying levels of oxygen, which, as we know, helps with the aging process, however, the oxygen permeable caps have not been perfected enough for high-end wines that are meant for ageing. Bolder and age-worthy whites, such as Chardonnay, and most reds still benefit from the natural cork. The most appealing reason for screw caps is the lower price.
Synthetic corks and screw caps do have their place, but since there is a whole industry around the production of cork, and it is a sustainable resource, it stands to reason that natural corks are here to stay. Somehow “let’s pop open a bottle of Merlot,” just sounds better than “unscrew that bottle of Blanc du Bois, would you?”