My favourite wine switched to a screw cap closure after using a natural cork for many years. What does that mean for its quality?
If there was any doubt about how much tradition rules wine, consider the seemingly endless closure debate. It’s been nearly 20 years since progressive producers, such as New Zealand’s Villa Maria and Niagara’s Flat Rock Cellars, went 100-per-cent cork-free and we’re still talking about whether a piece of tree bark used to seal a bottle of wine is an important sign of quality.
Originally the move to screw caps was a bid to eliminate the risk of cork taint. A common fault in wine, which can affect all prices and quality levels, cork taint imparts undesirable aromas or flavours into a bottle of wine. Trade estimates suggest as many as 5 per cent of cork-sealed wines may be adversely affected by a chemical compound known as TCA, which creates distinct wet cardboard or newspaper, dank basement and other musty notes.
Wineries in Australia, New Zealand and Canada were concerned that emerging wine consumers wouldn’t recognize that the musty aromas were caused by the cork. Instead of dismissing the issue as a corked wine, they might write off that winery.
While the cork industry has reduced the incidence of TCA taint in recent years, the threat still exists. Wineries now have the option of using guaranteed TCA-free corks, such as Amorim’s NDTech, which have undergone screening and treatment. These are more expensive than regular natural corks, and much more than screw caps.
But Ross Wise, winemaker at Black Hills Estate Winery and senior winemaker of Andrew Peller Limited’s South Okanagan wineries, explains there are other aspects to consider. “Wine quality comes from many factors such as its length, fruit intensity and purity, complexity, concentration and overall balance,” he says. Changing a bottle’s closure from natural cork to screw cap doesn’t alter any of those factors.
A New Zealand native and trained winemaker who has been making wine in Canada since 2006, Wise says consumers can expect a more consistent product when a winery moves to screw cap – especially as the wine ages. Bottles sealed under screw cap will age in a much more uniform manner compared with those bottled with natural cork due to a more reliable oxygen transfer rate (OTR), he says.
“Screw caps generally have a lower OTR than corks, depending on the screw-cap liner that the winemaker chooses. This can result in wines maturing more slowly than if they were sealed under natural cork,” he says. “This can be a positive or a negative, depending on the style of wine and how the consumer prefers to age and mature their wines.”
According to Wise, if your favourite wine now comes sealed with a screw-cap closure, its quality will not be affected, but the wine may mature more slowly than it used to with natural cork.
Considering the vast majority of wine purchased in this country is opened mere hours after purchase, aging isn’t a concern. The ability to open a bottle with a swift turn of the wrist will mean that bottle of wine gets opened even more quickly.