Screwcaps

I often get asked about screwcaps, particularly here in the US where most bottles are still stopped with corks. Screwcaps are slowly beginning to emerge for less expensive wines, but consumers still prefer corks, associating them with high quality as well enjoying that sound of a cork being pulled. Elsewhere in the New World, screwcaps are much more common: in New Zealand, around 70% of wines have a screwcap closure. I once met the actor Sam Neill, who owns the Two Paddocks winery in Central Otago, and asked him why he didn't use corks and he pulled a face of dramatic disgust, "You can never trust a cork."

The reason for his disgust was, of course, because corks have a tendency to become infected with TCA. As I wrote in a previous blog, TCA is a chemical compound that makes a wine smell and taste bad and comes from cleaning the cork with chlorine or unclean winemaking practices. This was an especially problematic issue in the 1990s, when possibly up to 10% of wines were infected with TCA. Things have got a lot better since then as the cork industry has worked hard to remedy the problem, but there's still a 2-5% chance of a wine being faulty, whereas with a screwcap that's nearly zero.

So why doesn't everyone use a screwcap?

The downside to screwcaps is that they arguably don't allow a wine to age as well as a cork does. A cork lets small amounts of oxygen to permeate into the bottle, allowing the wine to breathe, develop, and mature. A screwcap, again arguably, does not allow a wine to develop the same complexity as it is completely airtight. 

Many wineries are experimenting and coming to different conclusions. A few years ago, I visited the Andrew Will winery in Washington and the maverick, charismatic owner and winemaker Chris Camarda kindly poured me two versions of the 2008 Sorella, one of the great wines of the US. One bottle had been stopped with a cork (which is how the wine is sold) and the other closed with a screwcap. The differences were subtle, but the screwcap bottle was fruitier while the cork bottle felt more integrated and complex, with spicier and more oak flavours. That confirmed my impressions that a bottle stopped with a cork ages more gradually and complexly than with a screwcap. That was again confirmed by the recent decision of a leading Chablis producer, Laroche, to switch back to cork for their Grands Crus, having used screwcap since the mid-2000s but feeling that the wines were not ageing as gracefully as they would have wished.

it's complicated

However, as with everything in life, it's complicated. Last week my wife and I opened a 2006 bottle of Chardonnay from New Zealand producer Kumeu River (pronounced Q-mew River), based near Auckland where an increasing amont of quality Chardonnay is being made. Although they're a good producer (the owner and winemaker, Michael Brajkovich, is a Master of Wine), I wasn't expecting that much from a ten-year-old Chardonnay bottled with a screwcap. Quite the opposite: it was sensational. It was incredibly fresh - perhaps because of the screwcap - with rich, fruity green apple and citrus aromas, and a smokiness coming from oak. And - despite the screwcap - it had a slight nuttiness that I would normally associate with slow oxidation, something that with a cork may have been more pronounced. On the back of the label, Brajkovich stated that the wine would age for four to six years. Ten years later, it's still going strong, which shows how much we have to learn. One thing I can say, though: opening a screwcap is a lot easier and quicker than pulling a cork...

TCA

One of the most frustrating aspects of wine is the number of bottles that are faulty. A well-made beer or spirit tastes exactly like it should, while a wine, however well made, may taste nothing like it should. A faulty bottle of wine can be caused by a number of reasons, but the main one is TCA, a nasty chemical compound called in full 2,4,6-trichloronanisole. A wine affected by TCA tastes like wet cardboard, a musty room, nail varnish remover, and downright nastiness. Such a wine is often described as "corked," because the damage TCA causes comes from a reaction in the cork between penicillum mould (as found in blue cheese) and chlorine used in the sterilisation process.

The instances of corked wines came to a head in the 1990s, after a complacent cork industry failed to address the issue. Screwcaps and various types of synthetic cork were a response to the number of wines affected by TCA. New Zealand, as modern a wine country as there is, made a conscious decision in 2001 to reject corks and now just under 70% of wines are bottled under screwcap. Since the 1990s, however, the cork industry has certainly cleaned up its act - literally, as corks are no longer cleaned with chlorine, the main cause of TCA.

Estimates vary as to how much wine is corked. It may have been as much as 10% in the 1990s, falling to 5% today. Conscientious wineries should be aiming for 2%. That's still high - a winery producing 50,000 cases may be distributing 1,000 cases of corked wine despite their best efforts.

It requires a great deal of effort in combating TCA. Using screwcaps or thoroughly analysing corks may not be enough: it can be found in cardboard packaging, in the winery, even contaminating glass bottles. Also don't forget that if a wine has been stored badly - particularly in an overly warm or bright environment - it will also be faulty, regardless of how it's been stopped.

The number of corked wines is intimidating because the overbearing restaurant experience of a waiter pouring some wine for you to taste is for you to check whether the bottle is clean or faulty: determining whether that bottle is faulty or not requires skill, experience, and confidence. Often a bottle which a customer dislikes is faulty, but they lack the knowledge to describe it as such. Waiters and sommeliers can be too protective to admit that they are serving a corked wine - even though it's a regular and unavoidable part of the job.

I just undertook a test in which I smelt forty-five wines back to back. They were organised in rows of three, in which one was faulty and two were clean. The nine faulty wines had been deliberately tainted with TCA, but to various degrees. The hardest to detect had 1 part in a trillion; the easiest had 4 or more parts (most people can detect 7 parts per trillion - that's how potent TCA is). I spotted 8 of the 9 tainted wines, meaning I am now entitled to a certificate proving I am capable of detecting 1 part of TCA per trillion.

The organisers, Vinquiry, based in Sonoma County, claimed that spotting TCA is genetic, and certainly some people will find it naturally easier to spot than others. But I also think it's part of the experience of regularly tasting. Even if you're readily able to detect TCA, you still need to know how to describe it and distinguish it from a wine that's simply badly made. This is especially true of a wine that has the faint 1 part per trillion: spotting that small amount comes, I think, from the misfortune of regularly tasting corked wine.