Ditching screwcaps in favour of cork? Klein Constantia's surprising transition

Ditching screwcaps in favour of cork?
South African winery Klein Constantia makes a surprising switch

Last week I quizzed Klein Constantia winemaker Adam Mason (right) about his choice to switch back to cork from screwcaps for his top Sauvignon Blanc, the Perdeblokke. This has created a lot of discussion (for example, see Victoria Moore’s well reasoned piece here and the associated comments).

Klein Constantia first moved to screwcap for some of its wines in 2003, and the Perdeblokke Sauvignon was bottled under screwcap from 2006–2009. However, the 2010 vintage will be back in cork.

‘The Pederblokke was screwcapped but I always got a slight whiff of sulfide on opening it,’ explains Adam. ‘This is a lees-aged wine, and we are looking for some sulfide complexity.’

Adam says that making this switch was seen by many screwcap advocates as an admission of incompetence. They argue that there is nothing wrong with screwcaps: they just require a different approach to winemaking—and that giving up on screwcaps shows that Adam has failed to master this. But Adam sees this a different way. ‘Rather than compromise the winemaking,’ he explained, ‘I decided to go back to cork. I didn’t want to let the tail wag the dog. Why change your winemaking style to match the closure?’

‘By bottling under screwcap, we lowered the quality of the wine,’ says Adam. But he’s not anti-screwcap, and recognizes the importance of the emergence of alternatives to cork for helping the cork industry address issues of taint and inconsistency. ‘The best thing that happened to the cork industry was the screwcap,’ he states. To put this in perspective, Adam still uses screwcap for the 100 000 bottles of regular Klein Constantia Sauvignon Blanc - the shift is solely for the 3000 bottles of Perdeblokke.

Another gifted young South African winemaker, Duncan Savage of Cape Point, is also making a similar switch. ‘We went to screwcap for the first time in 2010,’ he says. ‘We’re going to change back to cork.’

Ultimately, this sort of decision making is prompted by an honest appraisal of how wines actually taste under different closure. It also recognizes that closure choice does affect the flavour of wine. It’s quite a shift from the prevailing Australian and New Zealand view, which unfortunately does not display such an open mind about closure issues.

There, many winemakers are extremely defensive about the suitability of screwcaps for all wine styles, and seem to dismiss the idea of varying oxygen transmission levels affecting the way that wine develops post bottling in positive ways. It’s almost like a religious belief for some: not open to discussion or challenge.

But even in Australia and New Zealand, many winemakers are considering switching away from screwcaps for some if not all of their wines. Some have already made the switch. The tin/saran liner—almost universally the one used—allows very little oxygen transmission. Such low levels of oxygen transmission may not suit all wines.

And they recognize that while still far from being a perfect solution, natural cork has improved greatly since the late 1990s, where its disastrous performance—both in terms of taint and variable oxygen transmission—was the great motivating factor in the widespread shift towards screwcaps.

Other alternatives to screwcap and natural cork also have a role to play. Diam is a technical cork, made of reconstituted cork fragments plus a small synthetic component, and is taint free because of the special cleaning process these cork fragments are subjected to. And while injection-moulded synthetic corks look to be on the way out, high quality co-extruded synthetics, of which Nomacorc is the market leader by some distance, offer another taint-free option for wines that benefit from higher levels of oxygen transmission.