Firmly on the Screwcap

The last decade has seen tremendous progress in research into and understanding of wine closures. Ten years ago, if you’d gone into a supermarket and scanned the wine aisles, they would have looked very different.

Screwcaps would have been non-existent, and the only alternative closures in use would have been the first-generation injection-molded synthetic corks, which were first introduced in 1996 by Safeway. The vast majority of bottles then were cork sealed, and cork wasn’t doing a particularly good job.

How things have changed. The global picture now is one where cork is still the dominant closure, but alternative closures have made significant inroads.Estimates are that of a global market for bottled wine of some 18 billion per annum, screwcaps are now sealing just over two billion of these bottles, while synthetic corks seal four billion.

But if we look at a more local level, there are countries where cork is in danger of extinction: screwcaps now seal around nine out of 10 bottles of New Zealand wine, and in Australia the situation is fast heading that way. In UK supermarkets, alternative closures are gaining a dominant position.

But perhaps even more significant than the change in closure usage has been the change in our understanding of what wine bottle closures actually do. Ten years ago, the general consensus was that the role of the closure was simply to seal the bottle, and the better it did this the better the closure.

Received wisdom was that a total (hermetic) seal, allowing no oxygen transmission (OTR), would be the ideal closure. While a few still believe this, the results of a significant scientific study conducted by the Australian Wine Research Institute (AWRI) have blown this idea out of the water, and changed the way we think about closures forever.