Wine closures -to cork or not to cork: that is the question?

Wine closures are an interesting subject, and one of great importance. Their function is to protect wine from oxidation, during its storage. Everyone dismisses them until asked directly the question, “To cork or not to cork?” From the initial question this becomes a very tense issue for some and a new challenge to be answered to others. It usually comes out to what the consumer wants out of the wine, and how they approach it. The decision usually falls to one side or the other depending on the following variables: corkage/TCA taint (“TCA” is explained below), oxidation, and aesthetic appearance.

So many people are hesitant to speak on this subject, for lack of wanting to make a firm opinion, or worried that there isn’t enough significant “data” to support their conclusions. “Lies, lies, and damn statistics!” coined by Mark Twain, meaning data will tell you what you want to get out of it as all variables are what you input. So people can be quite sensitive about closures, when they talk about them at all! There are so many factors involved in the closure’s debate outside of the actual product; there’s the lobby’s for the cork and alternative closure industries, PR people on both sides, and the wineries looking to their consumer base.

So here are all the options for wine closures with more to come, no doubt, in the future.

The Challengers to cork

Synthetic corksSynthetic corks are made from plastic compounds designed to look and “pop” like natural cork, but without the risk of TCA contamination. Disadvantages of some wine synthetic corks include a risk of harmful air entering a bottle after only 18 months, as well as the difficulty in extracting them from the bottle and using the plastic cork to reseal the wine.

Screw capsScrew caps or “Stelvin Caps” are closures made only from aluminium material that threads onto the bottleneck. They are now the predominant closure used by Australian and New Zealand wineries. Screw caps form a tighter seal and can keep out oxygen for a longer time than cork. These benefits aid in maintaining the wine’s overall quality and aging potential. Extensive quality tests show convincing results: apart from protecting against cork taint, screwcaps are also beneficial in the aging of wine, particularly preserving the aromatic freshness. Another advantage of screw caps and other cork alternatives is wine does not have to be stored laying down as with cork which must be kept moist so as not to dry out and shrink.

Vino-SealVino-Seal, or Vino-Lok, is a plastic/glass closure released by Alcoa. Since its introduction into the European market in 2003, many wineries have utilized Vino-Seal. Using a glass stopper with an inert o-ring, the Vino-Seal creates a hermetic seal that prevents oxidation and TCA contamination. A disadvantage with the Vino-Seal is the relatively high cost of each plug and cost of manual bottling due to the lack of compatible bottling equipment outside of Europe.

ZorkInvented and developed in Adelaide, SA, the Zork is an alternative wine closure that seals like a screw cap and pops like a cork. The Zork closure consists of three parts; an outer cap providing a tamper evident clamp that locks onto the European band of a standard cork mouth bottle, an inner metal foil which provides an oxygen barrier similar to a screw cap, and an inner plunger which creates the ‘pop’ on extraction similar to cork and reseals after use. An excellent alternative but it is relatively expensive.

Crown capsThe traditional crowned bottle cap has been used in the sparkling wine industry as a closure during the bottle fermentation process. Normally the cap is replaced with a cork before shipping, though recently some producers are releasing wines using the crown cap as their closure. The crown caps provide a tight seal without risking cork-taint. Although easier to open, crown caps eliminate part of the ceremony and mystique of opening a sparkling wine with a pop!

Cork the current contender