Cork manufacturers say the quality of corks is improving, and they may be right. But more vintners are choosing to bottle their wines under twist-offs than ever before.
Last year in our Napa office we encountered fewer bottles suspected of cork taint than in any year since we started keeping track in 2005.
Tasters flagged 3.5 percent of all cork-finished wines for being suspected of some kind of flaw, most often TCA, and marked them for retaste. (In fairness, "suspected" is the key word, since we don't send the questionable corks or wines to be tested by a lab.)
Of the 6,820 wines reviewed in Napa last year, 4,918 were bottled with corks and 170 were marked for retaste, giving us the 3.5 percent tainted figure. Our tastings include wines from California (3,695), Australia, New Zealand, Oregon and Washington. Of all those, 1,633, or 23.9 percent, were bottled under twist-offs—that's the highest percentage we've encountered yet, up from 23.1 percent in 2014 and 22.4 percent in 2013. Australia and New Zealand are ahead of the curve when it comes to twist-offs, with New Zealand's percentage around 90 percent.
Cork-finished wines from California showed the biggest drop in TCA taint, down to just 2.6 percent. The other aforementioned countries and regions had a combined 5.2 percent of their wines marked for retaste.
TCA-related cork taint is often obvious: Wines heavily tainted by TCA display pungent mold and chlorine odors and/or flavors. Low-level TCA is harder to detect, yet it affects a wine's flavor or body. Retasting a wine can often reveal these lower levels of taint: If it later shows better, an inferior seal or substandard storage conditions are presumed to have been the culprit(s) of the wine's earlier poor showing.
We count wines suspected of taint among those bottled under both natural cork, composite cork and cork alternatives, which we've been following for years. We don't track instances of suspected TCA taint for wines bottled under twist-offs, which occasionally show minor flaws such as oxidation, but in minuscule numbers.
Ever since the spotlight hit TCA taint in the 1980s, many closures have been tried, including synthetics, with twist-offs gaining the largest share among alternatives, particularly among early-drinking whites such as Sauvignon Blanc, Riesling and rosés and, to a much less extent, reds like Pinot Noirs. This reflects vintners' and consumers' approval.
No matter where you stand on the issue of closures, twist-offs are the clear winner when it comes to the frequency of flawed wines. My colleague Harvey Steiman recently conducted a tasting of older Chehalem Pinot Noirs under twist-off that suggested they're superior closures for aging wines as well. They are not now, and may never be, the preferred choice for the wines that vintners present as their best. But those who appreciate the advancements of twist-offs are making their case. Consumer acceptance is stronger with every vintage.
In the end, the last holdouts against the march of the twist-offs will be ultrahigh-end wines for which image and prestige trump quality.
2015: 2.63 percent tainted
2014: 4.53 percent tainted
2007: 9.5 percent tainted
2006: 7.0 percent tainted
2005: 7.5 percent tainted
For a counterpoint in the corks vs. screwcaps debate, see senior editor Bruce Sanderson's video with Domaine Laroche's Grégory Viennois on the winery's decision to switch from screwcaps back to natural corks.