After speaking with many of you during your wine purchases, we have noticed a widespread misapprehension of the Stelvin or screwcap closure on bottles. While we agree that the screwcap lacks the visual effect and character of a traditional cork, the functional benefits of a screwcap far outweigh the aesthetics. After all, it’s what’s in the bottle that ultimately matters right?

What makes a perfect cork?

In ancient times the Romans used olive oil to seal the amphoras of their wine. They believed the oil would sit on top of the wine and prevent air from affecting it. While olive oil provided all of the necessary components that we look for in today’s wine bottle closures, it is less practical today because of the often lengthy journey from the vineyard to your dinner table. Most importantly, a good cork should not breathe, that is, it should not allow for air exchange. Letting air into the bottle inevitably causes variation from one bottle to the next, as producers are unable to control the ‘breathability’ or porosity of the cork with any consistency. The ageing process for wine is anaerobic and, unlike traditional cork, screwcaps make a perfect seal.

Why was cork used?

Though its history can be traced back to early civilization, the application of cork as a modern day wine stopper was engineered by the 17th century monk, Dom Pérignon. Cork was ideal for because it was pliable enough to compress into the neck of a glass bottle, yet firm enough to stay in position and prevent air exchange.

What is TCA? What does it mean when a bottle is ‘corked’?

The chemical 2,4,6-trichloroanisole, or TCA, which is known to be present in natural cork, is the main cause of cork taint in wine (otherwise known as a ‘corked’ bottle). When you go to a fine restaurant and the sommelier pours one taste of the wine before filling everyone else’s glass, one of the things the taster is supposed to check for is cork taint. TCA, which is often undetectable at low levels, imparts an odor similar to that of wet cardboard or moldy newspaper when present at higher levels. Only about 1 – 2% of all bottled wine have high levels of TCA. A much higher percentage of wine is affected by low levels of TCA, which results in the loss of fruit and other flavors, without causing a noticeably unpleasant odor. While TCA is not the only chemical known to be present in cork and to cause damage to wine, it is the most prevalent.

What is so great about screwcaps?

While there is still limited empirical evidence to support the long term agability of wine under screwcaps, the interim results suggest that the longevity of wine in the bottle under screwcap is much greater than the same wine bottled under traditional cork. Screwcaps are made of metal coated with a polymer, which is similar to that of Saran Wrap and does not react with the wine. The use of a polymer ensures that the metal does not come into contact with the wine at all, and helps to create an airtight seal.

Despite the assertion that wine needs to breathe a little during its ageing process, there is simply too much variation in the current supply of cork and many consumers are tired of playing ‘Russian roulette’ with their fine wine purchases. Imagine (if you have not experienced it first hand) opening a bottle that you have been holding for 10 or 20 years only to find that it has oxidized and turned to vinegar. Many high-end producers around the world are betting that this spoilage could be prevented by using a screwcap and are setting aside a small portion of their production each year in search of proof. If it is shown that screwcaps do indeed extend the life of a wine, the implications would be far reaching and many of the gurus who review wines for trade magazines such as Wine Spectator would have to adjust their ideal drinking windows for all wines.

Unlike most industry trends, which are fueled by consumer preferences, currently, the push towards screwcaps is being driven from the top of the supply chain down to consumers. Those ‘in the know’ within the industry feel so strongly about the benefits of screwcaps, that they are essentially ignoring customers’ resistance to them.

Additionally, if you are interested in knowing more about this subject, below please find links to the articles we used in compiling our research for this article:

Steinman, Harvey (2006, June 13). Straight Dope On Screwcaps. Wine Spectator Online. Retrieved March 5, 2007, from,4211,268,00.html
Suckling, James (2006, October 27) James Suckling Uncorked: Screw Cap Brunellos and Barolos? Wine Spectator Online. Retrieved March 5, 2007, from,4211,572,00.html
Suckling, James (2005, March 31). The Genie in the Bottle: The Virtues of cork go Beyond Mere Science. Wine Spectator Online. Retrieved March 5, 2007, from,1275,4994,00.html
Amorim Coporation. The Natural Choice: History or Cork As a Wine Closure. Amorim Corporate Website. Retrieved March 5, 2007, from