The World of Wine – August 2009

The World of Wine

By Ceci Rodriguez

What  About Screw Caps?


In the last 5 years, we can find in the market a lot of wines sealed with screw caps. Many people don’t purchase them because they think that these are bad quality wines. This may be because we are used to seeing coolers and sodas sealed with the same caps; however, these types of caps were initially designed for wines. Screw cap technology is continuously being tested and improved.

One of the newest studies made for members of the enology faculty of the Université Victor Segalen in Bordeaux, compared the “kinetics of oxygen ingress” between corks, various synthetic closures and screw-caps over a three year period. The results were that the commonly used synthetic corks had the highest oxygen permeation. Natural corks had medium levels, and the screw caps allowed low amounts of oxygen.

This low amount of oxygen preserves the wine with a greater degree of freshness.

As we know, cork comes from the bark of the cork tree, and as an organic substance, cork can easy mold, and it lets air slowly seep into the bottle. Many studies have shown that at least 1 out of every 10 bottles with corks are tainted with mold. The name of this mold is 2, 4, 6 Thrichloroarisole or TCA. The wine will have a musty flavor if it is tainted. It is necessary to store our wine bottles upright, rather than lying down when corks are used.

If we have a bottle sealed with a screwcap, it could be stored upright or lying down, The bottles with cork have to be stored on their sides because the tree bark could dry out unless it is kept wet. The dry cork then lets in enough air to oxidate the wine, and the wine becomes less flavorful. With screw caps, it doesn’t matter.

And what about aging wines? It is possible to use screw caps on wines selected to age. This is because, as I mentioned, the low amount of oxygen permits a low oxydation and that is what wine needs to age. There is the headspace gas mixture of the bottle to provide the slight amount needed for most of the aging. The settling process is done without any need for oxygen.

Of course if you are a traditionalist and enjoy the cork and the ritual of cork-pulling, you are going to miss the aesthetic ceremony and formality of “uncorking” the wine bottle. But if this is the case, and the screw caps seem too modern and “industrial”, you may want to re-examine what is really most important to you. Some things have to progress with realistic re-examination. For example, the Greeks used long pottery containers called “amphorae”. They were beautiful; however the Romans developed glassmaking and glass bottles which changed storage forever.

Wineries around the world have started to use screw caps. New Zeland uses screw caps in 80% of its wines; Australia now uses screw caps in about 50% of their wines. Of course, if we have a bad quality wine sealed with a srewcap, keep in mind that you don’t like it because of its quality and not because of the screw cap.

For more information about Lake Chapala visit:

Ojo Del Lago
Latest posts by Ojo Del Lago (see all)

Leave a Comment

Your email address will not be published. Required fields are marked *