It's a big question that’s been fermenting for years among wine producers, from Bordeaux to California to New Zealand. Throughout history, corks have provided a fairly benevolent environment in which wines can mature. But there’s been a recent shift=from cork to metal among some producers as an increased amount of wine seemed to be suffering from cork taint, leaving some wine tasting musty and dull. The culprit, which can spoil up to one in twenty bottles, is trichloroanisole (TCA), a compound formed when chlorine used for bleaching reacts with mold already growing in the cork. Humans are incredibly sensitive to the compound and can detect it even in weak dilutions. The problem with tainted corks is thought to be on the up because cork manufactures are finding it increasingly hard to find supplies of good quality cork to meet an increased demand; though there’s some evidence the cork industry is turning this trend around.
What About Synthetic Cork?
Of course, another alternative is synthetic ‘cork’, which is already in widespread use; but many vintners realize these do not provide a tighter seal than natural corks, many tasters complain of ‘plastic taint’, and many consumers find them difficult to remove and impossible to recycle.
An Industry Stance?
There is no official view yet among wine industry professionals. The general consensus is that it is up to the producers to decide how to close their wine. Everyone does agree that slow oxygenation is needed to age some types of wine. Screw cap proponents argue that wine is aged by oxygen in the wine itself and the tiny amount of residual air held between the cap and wine, while many producers remain resolute in their belief that oxygen is able to gradually seep through cork and into the bottle, and that this is the only way wine can mature.
And One More Thing…
Then we’re observing in Australia and New Zealand, where screw caps are plentiful, their solution to overcome the major obstacle facing screw caps—post-bottling sulphide reduction—is to dose wines with ‘heavy metal’ in the form of copper sulphate. No telling yet whether it’s something we’d embrace here; but, to purists, this philosophy demands that wines must adapt to its container, not the other way around. Where most people want fewer chemicals in their food and drink these days, screw cap advocates seem to be stepping in with more.
V. Sattui’s Position: Yes and No.
Our belief is that people haven’t attempted to keep wines for a long time with a screw cap, so we’re not going to switch wholly to metal closures without better evidence. While some wineries have taken the lead (risk?) in switching entirely to screw caps, we prefer to take small steps and have bottled six of our wines in metal closures. We believe they’re fine for maintaining freshness and fruitiness in our wines meant to be consumed early. So far we’ve seen no compromise in quality, nor has it met much customer resistance. But we’ll need more empirical data before moving further. We’re pretty sure that for long-term aging, cork is still it. Meantime, it seems change is likely to move at the pace of a maturing fine wine—all in good time.