Since Yalumba winery in South Australia commissioned a screw-cap closure for its riesling wines in 1959, winemakers and consumers continue to question the effectiveness and acceptability of alternatives to corks.
Behind the search for a replacement for the traditional cork stopper is the very real problem of wine spoilage caused by corks tainted with a chemical compound called trichoroanisol (TCA).
Once in the wine, it masks the normal fruit characteristics with a smell described as moldy or similar to wet cardboard.
Depending on who is asked, TCA affects anywhere from three to 10 per cent of all wines using cork – hardly a small matter considering the price of many fine wines.
Wineries in Bordeaux and California are known to have lost the majority of entire vintages to TCA whether from corks or other winery contamination.
Synthetic corks are problematic in opening and nearly impossible to reinsert. Agglomerate stoppers made from cork particles bound by polymers have gained acceptance although they also retain the image of use only for cheaper wines.
The Zork, a patented stopper that includes a snap-on seal that provides the traditional pop heard with corks, are useful but expensive option.
The primarily Portuguese cork industry has fought the assault on their near monopoly on wine stoppers with some disingenuous claims, not least that wine can’t age unless it breathes through cork.
Research at leading oenology schools has shown that wines evolve in completely oxygen free, or anaerobic, conditions and that exposure to air in any amount hastens spoilage.
Claims have also maintained that anaerobic screwcaps result in reduction which creates sulfur odours similar to rotten eggs. Further tests showed that while instances of reduction had occurred in some screw-capped wines the problem existed before the wines were bottled.
New Zealand now bottles over 85 per cent of its wines with screw caps. Many wineries now send their best wines to competitions under screwcaps to avoid problems with TCA.
A layer of olive oil kept air away from wine a few hundred years ago but gave way to corks, just as they will to innovative new closures.
It’s called progress.