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When to Put a Cork in It

The trials of two winemakers with screw caps are part of broader momentum shifts in the Great Closure Wars

Posted: Jan 7, 2014 1:00pm ET

By Ben O'Donnell

In recent years, the shift from cork to screw cap seemed inevitable. Forward-thinking regions like Australia and New Zealand now use screw caps for around 70 percent and 90 percent, respectively, of all their wine to better protect the quality.

So it came as a surprise two years ago, when winemaker Adam Mason, working for South Africa's Klein Constantia at the time, announced that he'd be returning the Perdeblokke Sauvignon Blanc to cork, after four vintages under screw cap—for technical reasons. Not long after, Christian Canute of Barossa's Rusden Wines made the same switchback on the Driftsand Grenache-Syrah-Mourvèdre, after five years under metal, despite an Australian wine press hostile to cork. "There is a fear that non-conformity on this issue might affect how a producer's wines are rated," Canute told me.

Could it be possible that the screw cap is not the closure panacea it's made out to be for all grapes and styles?

Screw caps eliminate two key problems in wine: muted, musty aromas from cork taint, which is caused by the chemical TCA that can form in the cork itself, and oxidation due to imperfect corks. But screw caps have their own issues, simply a function of how the cap works: Most seal the wine off from oxygen nearly entirely.

In winemaking, sulfur compounds, including volatile ones such as hydrogen sulfide (H2S) and mercaptans, can form naturally (along with the sulfur dioxide, or sulfites, added as a preservative). These usually blow off with exposure to oxygen, but in a wine starved of air, the volatile compounds can become trapped and possibly worsen in bottle. The result is "reduced" rotten-egg or stewed-cabbage aromas, the flip side of wines exposed to too much oxygen.

A winemaker's stylistic decisions can abet reduction: from the choice of yeast (some produce more hydrogen sulfide) to extended fermentation to racking regimens to bottling an unfined and unfiltered wine. These otherwise sound techniques can all increase the level of potentially bad sulfur compounds, like mercaptans, during winemaking.

Even when apparently tamed into undetectable forms with oxygen exposure, such pests emerged again in the reductive environment under screw cap, Mason and Canute found. Fresh, screw-capped wines later opened up with nasty surprises.

Some grapes—like Sauvignon Blanc, Syrah and Pinot Noir—lend themselves to reductive winemaking, the deliberate effort to limit oxygen exposure. These varieties have delicate aromas and flavors that can be "irrevocably lost as a result of certain oxidative winemaking practices such as poorly timed or too-frequent racking of the wine," explained Mason. You want to blow off any stinky sulfides without letting the enjoyable aromas and flavors float away.

Mason and Canute felt that using cork closures, which generally allow small amounts of oxygen to reach the wine, was the best option to manage the balance between oxidation and reduction for the cuvées in question. Why should winemakers need to ditch desirable techniques just so they can bottle under screw cap?

Undoubtedly, if you open a wine bottled under cork 10 or more years ago, you have a higher risk of cork taint than you will see in today's bottlings: The closure debate has sparked major research and development initiatives in the cork world aimed at reducing the incidence of TCA. While someone my age finds the occasional corky bottle, frequent TCA frustrations may be the heartbreak of an earlier generation of drinkers.

There are other compelling reasons to reconsider cork today. For wineries concerned about their environmental impact, natural cork is sustainable, biodegradable and has generally been found to leave a smaller carbon footprint. A new consideration is the promising invention of the Coravin preservation system, which allows you to extract a glass of wine from a bottle without opening it, using a needle that penetrates the cork.

Yet like the cork companies, screw cap makers have been striving to improve, continuing to invent and refine liners with varying levels of oxygen permeability. And winemakers now have access to more options than ever, whether synthetics or bioplastics, like those from Nomacorc; cork composite, like Diam; or even alternative packaging, from cartons to kegs.

What's the lesson here? The Great Closure Wars have taken to new battlegrounds: The debate of today plays out less in the opinion pages than in the cellars, where winemakers are fiddling with the whole spectrum of ways to seal wine to determine which best fits each bottling.

My exchanges with Mason and Canute demonstrate that some talented winemakers have found that they and their customers were unhappy with screw-capped wines—and cork fixed the problem. Making wine is an experiment itself, year-in and year-out, with a dizzying number of variables. I don't think it makes sense to be more dogmatic about the absolute merits of a closure than we are about any of the other hundreds of decisions winemakers consider in the yearly roller-coaster ride to a solid wine.

You can follow Ben O'Donnell on Twitter, at twitter.com/BenODonn.

Kelly Carter
Colorado —  January 7, 2014 11:52pm ET

Your colleague Mr. Laube has written extensively with the other viewpoint. James if you are reading, I think I speak for many readers when asking the question is the problem Ben speaks of regional (Australia and New Zealand)?

For example, I believe Michel Laroche in Burgundy (Chablis) bottles his Grand Cru with screw cap only. There is a WS video with Bruce Sanderson and Michel tasting the screw cap and cork wines from the same vintage and terroir, and Bruce noted in the video how much fresher the screw cap wine was.

My own bias is Austrialian wines are not enjoyable, and they are consistently too hot. I have tried to love them and don't bother buying them any more. I don't drink Sauvignon Blanc so I can't comment on New Zealand wines.

I have consumed Chablis, German Riesling, and California cabs with screw cap. I cannot recall having a bad experience with any of the wines tasted under screw cap.
Ben Odonnell
New York —  January 8, 2014 1:30pm ET
Interesting question, Kelly. You are correct that I'm probably in the minority at WS on this issue (though I'm certainly not against screw caps, nor are Adam and Christian, the winemakers—both bottle some wine under metal).

I think it's regional in the sense that the Southern Hemisphere regions, especially Australia and NZ, have embraced screw caps much more broadly than others, and therefore you'd statistically be more likely to find a bottle with cap-related reduction issues.

Getting to a more granular level regarding location and reduction, Canute had this interesting observation (one cause of higher H2S levels in winemaking is a lack of nitrogen for the yeasts during fermentation): "From my experience in the Barossa, grapes (not just Shiraz) grown on certain soils that have lower nitrogen levels do have a greater propensity to the production of H2S during primary fermentation. These wines are more likely to show up as reductive later on when in bottle. Generally the heavier red/black soils are lower in nutrient and produce higher H2S."

Ben O'Donnell
Wine Spectator
Harvey Steiman
San Francisco —  January 8, 2014 3:20pm ET
Also, with respect to the reduction issue, I taste a wide range of Australian wines under twist-offs, and encounter LESS reduction than I do in wines I taste under cork.

My theory is that winemakers who use twist-offs pay more attention to the chemistry of the wines and make sure they address any potential issues before they bottle. As Canute says, this can put some restrictions on the winemaker, but I taste a wide array of styles bottled under twist-offs. In my view the overriding issue is whether consumers are going to get what the winemaker wants, or will the closure ruin it for them.
Harvey Steiman
San Francisco —  January 8, 2014 4:43pm ET
In my view the elephant in the room is that every bottle under cork is different from every other bottle, blatantly corky at one extreme, at the other so subtly affected we hardly notice. It's the ones in between that are so maddening, each one letting in a bit more or less air than others, or imparting a woody flavor, or leaking. Over time, these differences get more pronounced, some producing perfectly aged bottles, others in various degrees of being not quite what we wish them to be.

For cork taint, full blown corkiness is easy for most of us to spot (although some people don't seem to notice). More vexing are the wines where TCA has clipped or muted the aromas and flavors. I've lost count of the number of times I have asked a vintner pouring samples at an event if the wine in my glass is what it should be, and a second bottle is much better. Never happens with screw caps.
Vince Liotta
Elmhurst, Il —  January 8, 2014 9:29pm ET
Ben, You're right. Us older folks have put up with a lot more corked bottles than younger folks. And it is certainly true that the incidence of corked bottles has decreased. But how many corked bottles is too many? Even in this past year, in this "improved" era of cork closures, I have encountered corked bottles at trade tastings that were half empty. Yes, this means the professional pouring it plus all the professionals who tried the wine before myself were apparently oblivious to the defect. It feels like fraud!

Lets face it. The vast majority of bottle closures are chosen for marketing reasons, to fulfill an expectation or an image. New Zealanders have done well with screw-caps not only because they show their wines well, but because it is a way of distinguishing themselves in the market-place.

Like Harvey, I don't see the reductive problem as an excuse for not using screw-caps. And screw-cap bottles do indeed oxidize over time. In fact, in the short term, a screw-capped bottle oxidizes more rapidly than its corked counter-part as there is a greater amount space, i.e. oxygen, between the top of the fill and the botttom of the closure.

I am entirely open to the full array of options--I'd like to see more development with glass closures--but whatever a producer chooses, I would hope it guards against unnecessary contamination or oxidation.

Andrew J Walter
Sacramento, CA —  January 9, 2014 12:04am ET
Harvey -- do you (or the WS) keep a record of "tainted" wines bottled under cap? I've had a number wines under cap and never have seen an issue with reduction…so it would be interesting to know these results in a larger sample.
Harvey Steiman
San Francisco —  January 9, 2014 11:43am ET
Andrew, I don't keep a record of how many wines show reduction characteristics (the telltale rotten egg stink combined with tight mouthfeel). But I simply don't find them much in wines bottled under spiral. Wines bottled under cork seem to be the ones where something's lurking in the flavor profile that will require a second bottle to verify.
Don Rauba
Schaumburg, IL —  January 11, 2014 9:24pm ET
I just dumped out two bottles of 2005 bordeaux because of TCA (and the retailers are out of business so I have no recourse). Different producers, different sources, both corked. In ONE night. Imagine how amused I am about this story about reverting to cork. HA HA. I'm sure the bordeaux are having a good laugh at us pretentious idiots: they're selling us such volumes of TCA tainted wine, pretending it's "elegant", "woodsy" and exemplary of "terroir". I'm not only ENRAGED I now will never buy French wine again. EVERRRRRRR... (don't look so smug, Argentina, I've opened enough of your corked Malbec to tip a ship and swore you off a year ago.)
Scott Creasman
Atlanta, GA —  January 13, 2014 10:00am ET
It has been a few years since I read Taber's To Cork or Not To Cork, but wasn't one of the historical reasons behind NZ/AUS early adoption of screw caps was the belief that they were getting inferior cork (the best going to France, Italy, U.S., etc.)? NZ Sav. Blanc might lend itself to screw caps, but NZ winemakers also thought they were pushed that direction by a cork industry that didn't seem to care about them. The cork industry created an environment of failure that would have never been tolerated in any other sector and begged for competition.
Joseph Byrne
CA —  January 13, 2014 1:32pm ET
Harvey excellent points as always. Maybe James Laube can comment too? I always go back to Jamie Goode's explanation on reduced wine. These reduced wines can be addressed before bottling and its a shame the industry blames the screwcap for the winemaking flaw. The leaky cork can then sometimes "fix" the flaw. Maddening.

Don should tell the Wineries next time about the corked wine and send them the number from the bottle and/or cork. Did that with Andrew Will and they sent me 2 bottles to replace the corked ones. Nice.
Joel Viger
Cranbrook B.C. —  January 16, 2014 3:03am ET
In looking at the Top 10 wines of 2013 it's interesting that they are all using cork closures! Who's going to tell those vintners that they are doing it all wrong?

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