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Fighting the Smell of Bad Wine Corks

Fighting the Smell of Bad Wine Corks

Can composites eliminate the problem? We went to France and Spain to find out

For the past few hundred years, wine bottles have been sealed with a spongy plug punched from the cork bark of a special oak tree grown around the Mediterranean basin.

For the past few hundred years, wine bottles have been sealed with a spongy plug punched from the cork bark of a special oak tree grown around the Mediterranean basin, and everyone was pretty much satisfied with that arrangement.

Click here for the Fighting the Smell of Bad Wine Corks Slideshow

Then, with increased worldwide demand for wine in the 1980’s, we started noticing that more wines we opened had the musty smell of a time capsule from our grandparents’ attic. We had sniffed it before – cork taint, TCA or trichloroanisole – but now it was more frequent, ruining even our most expensive wines. We said, “We’re not going to take it anymore!”

The race was on for a better closure – screw caps, synthetic corks, composite corks, glass stoppers and simply better-selected, steam-cleaned punched natural corks. But even steaming corks didn’t eliminate all TCA, and substitute closures didn’t have all the advantages of corks, such as air permeability, elasticity and handsome looks.

DIAM Bouchage, one of the companies that make composite natural corks, thinks it has the TCA problem licked and has been working the past half-dozen years to better punched corks on physical properties as well.

DIAM invited me to Spain and France to take a look – and a smell.

Are You Making This Big Mistake with Wine Corks?

The Wine Wise Guy explains why becoming a cork-sniffer is a very bad idea.

A few years back, when I was studying to earn my 𠇍iploma in Service” with the Sommelier Society of America (a school for wine professionals in New York City), I remember perspiring my way through the final exam, a pretend wine-service exercise. Two top sommeliers, Roger Dagorn (our terrifyingly-serious-but-charming French head teacher) and his right hand, the lovable “good cop,” Renzo Rapacioli, sat at a fully-set table playing hard-to-satisfy wine-ordering customers I played the sweaty sommelier. Whenever I glimpse an episode of Shark Tank, I’m immediately transported back to that table-side interrogation, where I dodged grenades like “What might you suggest if I order the skate au beurre noisette, but my companion orders the boeuf Bourguignon?” and, “How many premier cru Burgundy vineyards are represented on your wine list, per chance?” and my favorite, “Would you say there’s a higher percentage of Tinta Roriz grapes in this Port or Tinta Barroca? Or perhaps even a touch of Tinta Amarela?

If the oral examination part wasn’t terrifying enough, there was also the demonstration portion, which included everything I hate about formal (read: French) wine service. From the presentation of the bottle, swaddled in white linen like a new-born baby, straight through to decanting it with trembling hands over a candle (to look for sediment) on a tableside trolley, it bugs me. Personally, I bundle most of these maneuvers into what I call “the frippery” of wine service: stuff that makes most people I know slink down in their seats in hopes that the sommelier will call on someone else to taste the wine.

But then I see that person: The Imbiber. He&aposs the one𠅊nd it&aposs always a man—who relishes the pageantry of it all, the pomp and circumstance, who imagines that everyone else in the room is intently watching this noble ceremony take place. And when the sommelier places the just-pulled cork on the table to the right of the glass, The Imbiber picks it up ceremoniously, rolls it between his thumb and forefinger, and takes a deep, satisfying sniff.

The Imbiber deserves to be dunked in a barrel of wine.

Rolling a cork—which is just a piece of bark from a cork tree, after all�tween your thumb and forefinger is just plain silly. And sniffing it? Sillier. That is, unless (and this is an important unless) you’re the person pulling the cork.

Here’s why. If I’m pulling a cork out correctly (meaning, aiming the worm of the corkscrew, i.e. the part that looks like fusilli, straight down through center of the cork), I can tell on the first, careful turn of the screw whether or not that cork is going to come out easily or not. If not, there are a number of possible reasons. It might fall apart because it’s too old it might snap in half because it’s brittle the center of it might disintegrate, because it&aposs soaked through and crumbly. If any of those things happen, there’s no cork to present to The Imbiber.

But if the cork comes out as it should, in one healthy piece, there’s no need to roll it around between your fingers. If I&aposm the server, yes, I’ll immediately smell the wet end to see if there are any “off” odors that might indicate the wine is flawed, damaged, or just plain dead. The wet end of a cork is still moist and porous, but the liquid at the tip either absorbs or dissipates pretty quickly. And a few seconds later, the cork smells like… cork. End of story. So why put it on the table? Because The Imbiber wants to show off. He wants to pick it up and sniff it slowly, thoughtfully, giving the world the impression that he&aposs learning something vital from it. And in my experience The Imbiber doesn&apost even smell the end of the cork, which actually might tell him something. No, instead he passes it sideways under his nostrils as though it were a cigar. 𠇊h yes, excellent,” says The Imbiber, putting the cork down again. Really? Excellent what? Excellent tree bark?

I𠆝 be lying if I didn’t admit that I, too, occasionally like some of the pomp that comes with wine service, especially if it’s a festive gathering and the sommelier plays to the crowd. But at the end of the day, all the customer really needs to do is give the glass a swirl and a sniff, assess if the wine has any of those “off” aromas, confirm that decision with a quick a taste, and, if all is in order, say, “Perfect. Thank you.” I mean, unless you really like having sommeliers think you&aposre a twit. In that case, go right ahead, smell all the corks you want.

How & Why You Smell The Wine In Your Glass

Now that you’ve looked at the wine and swirled it around in your glass, there’s only one more step before you get to drink it: smelling the wine.

When you smell a wine, you’re preparing your brain for the wine you’re about to taste.

When you smell a wine, you’re preparing your brain for the wine you’re about to taste. Our sense of smell has a profound affect on the way our brain processes flavor. If you want to better understand just how profound, hold your nose and then put a strawberry in your mouth and start to chew. Halfway through chewing, release your nose. You’ll notice right away how much more you actually taste when you have your sense of smell. This is why smell is so important when it comes to tasting a wine.

It’s Time To Learn How To Smell Wine!

When you go to smell the wine, stick your nose all the way into the glass and close your eyes — sure you might feel silly doing it, but you’re going to notice a lot more smells this way — then breathe in deep. As you smell the wine, think about what scents you’re picking up, and keep in mind that there are no wrong answers! If it’s a white wine, maybe you smell bananas, lemon rind, pineapple or even that scent that is always in the air when you go to the beach. If it’s a red wine, you may smell prunes, cherries, strawberries, peppers, plums or tobacco. In both situations, you may say you just smell grapes, and that is totally fine too. Your brain can only pick up scents that are in your memory, meaning they are scents you’ve smelled before or smell often. That’s why ten people could be sitting around a table smelling the same wine and say they smell ten different things!

Now that we’ve given our brain some material to ready our taste buds, we want to determine if we’re picking up any scents that could signal that something could be wrong with the wine, such as the wine being corked. A corked wine is not pleasant to drink, so if you smell anything that is reminiscent of wet newspaper, a moldy dank basement, old wet rags or wet dog, there’s a chance the wine is corked. If you’re not sure, feel free to ask those drinking with you if they pick up similar scents, and never be afraid to ask your server what they think, because if the bottle is corked, they should replace it. A good rule of thumb to remember here is that the only way a wine can be corked is if the wine bottle was sealed using an actual real cork. If instead the wine is closed with a screw cap or synthetic plastic cork, having a corked wine is not possible.

Now that you’ve assessed the wine for any irregularities, learned how to sniff wine, and readied your taste buds, the next step is drinking!

The Six Aromas You Don't Want to Smell in Your Wine

When you stick your nose in a glass of wine, what do you smell? Most of the time, the aroma will be fruity, floral or spicy. The wine may even be earthy or smell of smoked meats (as in a Northern Rhone Syrah), or buttery and tropical. All pleasant scents. But what if you smell rotten eggs, wet newspaper or a barnyard? More than likely that wine is flawed. And that's a wine you don't want to keep in your glass. If you're at home, dump it down the drain at a bar or restaurant, send it back (more on this later).

One of wine's dirty little secrets is that there are bottles on the market that contained flawed, faulty juice. Some times a wine gets spoiled somewhere along the way in the winery, and some times it happens after bottling, during shipping or storage at a retail or restaurant location or even in your home. You know how wine is supposed to be stored at about 55ºF, in a dark space with low humidity and no vibration? This doesn't always happen.

I recently completed a course at the Culinary Institute of America in Napa Valley called "Sensory Analysis of Wine." The thing that made me want to take such a technical sounding course (which it wasn't) was learning how to identify flaws and faults in wine. I know many of the good aromas, but I didn't know the bad, or off aromas. It's possible I've sipped a few faulty wines but didn't know it and just thought the wine was funky. You've probably done that too, or perhaps you had a glass of wine you didn't like but couldn't say why. Most likely it was flawed.

We went through six common wine odor defects. Once you know them, you'll be able to smell them right away.

Oxidized -- The wine will smell like a sherry, and may smell stale, nutty or even like burnt marshmallow or stewed fruit. The wine's color can offer a clue too. Usually an oxidized wine will be turning a shade of brown -- brick red for reds, and golden to tawny for whites. An oxidized wine can mean it was subjected to hot temperatures, was not stored properly or was exposed to air. If you order a wine by the glass and it smells a little stale, ask how long the bottle has been open it's probably been a few days. Not good. Keep in mind a newly opened bottle can also be oxidized.

Volatile Acidity -- Does that glass of wine smell like vinegar or remind you of nail polish remover or Easter egg dye? Volatile Acidity (also called VA) is the culprit, and it is a bacterial spoilage.

Sulfur -- I had a strong reaction to this glass, and it wasn't a good one. Stinky and offensive, hydrogen sulfide has the unmistakable scent of rotten eggs. While sulfur is used in winemaking to prevent microbes and bacteria, overuse or improper use can cause it to form hydrogen sulfide or dimethyl sulfide. (Not to be confused with sulfites.)

Brettanomyces -- For years I've heard the term "brett," and that some people love what it does to wine and others do not. But I didn't know what the heck it smelled like until this class. Think of cherry cough syrup, Band-aids, or smokey, barnyardy or horsey aromas. I'm told a sweaty horse blanket is a ringer for brett. Brettanomyces is a yeast spoilage. Old world wines may have a tiny amount of brett that some wine drinkers covet. You can also find brett in some Belgian Trappist beers

Cork Taint -- I know what a corked wine is. But I am still surprised at how many of my friends and family don't know it when it's stinking up their glass. This means that the wine's been spoiled, or tainted by a chemical called 2,4,6-trichloroanisole, or more commonly TCA, that can develop in cork. When I smell corked wine, it's wet newspaper, dank basement, wet shaggy dog and musty. While the wine won't hurt you if you drink it, it's not a pleasant beverage because the cork taint will mask fruitiness. Open another bottle of wine -- odds are that even if it's from the same producer it's not corked. But get a new, clean wine glass. The corked odor hangs around even after you've dumped the wine out.

Sulfites -- Get a matchbook and strike a match. What you are smelling is sulfite. Sulfur dioxide is a sulfite, and a common antioxidant added to wine, to prevent bacterial contamination. You may get this odor from a newly bottled wine.

If you find any of these flaws in your wine glass, dump it out, send it back. Sure, sending a bottle back, especially an expensive one, is intimidating. The best way to handle this is to ask your server or the wine director to confirm what you are smelling. He or she should promptly send out a new glass or bottle. What gets people in trouble is sending back a wine because they don't like it. But wine and restaurant professionals realize that wine comes with faults. If you bought the wine from a grocery store or wine shop, cork it up and take it back to the retailer as soon as you can. You should get a replacement bottle or a refund.

The mysterious case of the cork-tainted carrots

A few months ago, UC Davis professor emeritus Linda Bisson &mdash who has some great quotes in my column this week &mdash told me something that completely blew my mind.

Bisson taught an introductory wine production course at Davis for some 30 years. One of the class objectives was to teach students to identify wine flaws, such as 2,4,6-trichloroanisole (TCA), otherwise known as cork taint. Students would be given a sampling of corks, some infected with TCA and some not, and asked to separate them.

&ldquoIn the beginning it was one out of 100 students, maybe one out of 200, who couldn&rsquot detect TCA,&rdquo says Bisson. &ldquoBut then, over time, it started to be higher and higher percentages of the students.&rdquo Was an entire generation becoming immune to that aroma &mdash revolting to many wine drinkers, including yours truly &mdash that makes a wine smell like wet cardboard and chlorine?

Then Bisson realized the culprit: baby carrots.

&ldquoThose plastic bags of baby carrots &mdash they spin them down, shape them, then bleach them, before putting them in plastic,&rdquo Bisson says, &ldquowhich puts them at a high risk for developing TCA.&rdquo The same chemical compound that can infect wine corks, in other words, has infected bags upon bags of processed carrots at the grocery store. Her students had grown up eating these carrots and had become inured to the taste and smell of TCA. In fact, they liked it.

&ldquoTo them it wasn&rsquot negative,&rdquo she continues. Baby carrots, for her students, connoted snacks packed by mom in the lunchbox the taste was linked to pleasant memories of childhood. &ldquoThey were perfectly happy drinking this wine that would turn our stomachs.&rdquo

This TCA discussion brings up many of the same issues I encountered when researching my column for this week&rsquos Food section, about the spoilage yeast brettanomyces. Why, I wondered, has a growing contingent of craft brewers embraced brett, which most wine and beer drinkers have long associated with offputting flavors like horse manure and Band-Aid? I became especially interested in this question when I found out that Napa winemaker Mandy Heldt Donovan, of Merisi Wines, is making an intentionally bretty Pinot Gris. (Maybe not coincidentally, Donovan worked in Bisson&rsquos lab as a graduate student.)

My central question is: Can our tastes collectively change over time, as baby carrots seem to have shifted the palates of the latest generation of Bisson&rsquos students? And is it possible to unlearn what we find disgusting &mdash to rewrite those emotional associations we have with certain flavors or aromas?

Funny enough, these questions intersect with another story I&rsquom publishing this week &mdash and this one isn&rsquot a wine story at all. It&rsquos about a different Mandy, Mandy Aftel, a well-known producer of natural perfumes in Berkeley who now operates a &ldquosmell museum,&rdquo the Aftel Archive of Curious Scents. I highly recommend a visit to the museum, where you can smell substances including hyraceum (the urine and feces of the hyrax, a small, furry mammal) and ambergris (essentially, whale vomit). Trust me when I tell you that both smell amazing &mdash floral, earthy, sweet, fruity.

I definitely never thought I&rsquod find the smell of animal poop preferable to a baby carrot.

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Where I&rsquom drinking

Owner Olivia Maki pours a glass from the cider taps at Redfield Cider Bar in Oakland, Calif. Saturday, Feb. 2, 2019. Jessica Christian / The Chronicle

The cider revolution seems long overdue. Cider checks all the boxes of current culinary trends: it&rsquos fermented, it&rsquos low in alcohol, and it&rsquos got small-scale agricultural credentials. As our culture embraces flavors of funk with increasing enthusiasm (see above re: whale vomit, horse manure, etc.), the traditional, bacterial ciders of Spain and France seem ideally poised for a big debut.

Enter Redfield, a new cider bar and bottle shop in Oakland that aims to make cider approachable and enjoyable for all sorts of palates &mdash for lovers of sour beer and natural wine as well as lovers of off-dry Moscato. If the cider revolution has a chance of catching on in the Bay Area, Redfield looks like the one to make it happen. Check out my review of the bar in this week&rsquos Drink Up column.

What I&rsquom reading

&ldquoIt&rsquos happening: For the first time, California has a truffle season,&rdquo writes my colleague Tara Duggan. Black Perigord truffles, long considered a pipe dream in California, are now starting to proliferate, including at a Jackson Family Wines property in Santa Rosa.

Planning to make a Valentine&rsquos Day trip to Wine Country? Chris Macias has suggestions for romantic winery visits in The Press.

Frequently bought together


"Fascinating. This discussion not only is relevant to today's wine producers and enthusiasts but will continue to stimulate interest until the 'perfect' bottle closure is developed. Highly recommended, especially in wine-producing and -consuming areas."
- -- Library Journal (starred review)

"In 'To Cork or Not To Cork,' Mr. Taber does an able job of telling the story of the cork industry's early history, its rise to global monopoly status and the recent search for alternatives. "

"'To Cork or Not To Cork' reads like a novel. While the book contains some scientific terminology and at times appears to be highly technical, even a non-scientist can understand it, and it's an easy and fascinating read."
-- Napa Valley Register

"No matter where you stand on the great debate over corks -- love 'em, hate 'em, or still undecided -- To Cork or Not to Cork: Tradition, Romance and the Battle for the Wine Bottle by George M. Taber, gives the subject a timely and thorough examination. Taber is a good storyteller and the book reads and flows easily."

"Taber is well-qualified to tell the story. He was the Time magazine correspondent on the scene in Paris for the 1976 blind tasting that proved American wines could not only hold their own but beat the best of the French. His 2005 book on the tasting, 'Judgment of Paris,' is the theme for two movies now in preproduction."

About the Author

Excerpt. © Reprinted by permission. All rights reserved.

Trust Your Senses of Sight, Smell, and Taste

Just because the cork and ullage look normal doesn’t necessarily mean the wine is in good shape. The wine could have a flaw that isn’t easy to identify by looking at the bottle alone. Follow these four steps after opening the bottle and before you take your first sip.

Step 1: Check the Base of the Cork

When you remove the cork from the bottle, check its base (the part touching the wine) it should be only slightly stained from the liquid. Corks that appear to have soaked up a significant amount of wine or that crumble to the touch are possible signs that wine has gone bad in storage. Soggy corks are those that were not well sealed to the bottle, allowing liquid to seep up around the edges. Likewise, crumbling corks are not dense enough to protect the wine from oxidation, increasing the likelihood of a spoiled wine. However, keep in mind that some older bottles of wine, particularly fortified wines like port , naturally have crumbly corks. The corks wear down over time, so don’t be too worried if the cork in a 50-year-old bottle of Taylor Fladgate crumbles a bit. The wine inside is likely perfect.

Step 2: Look at the Color

Pour yourself a glass and look at the color it should look like other wines of that variety and from that region, with only slight variations in hue. For example, Cabernet Sauvignon can range from a bright ruby to an inky purple depending on the producer, vintage, and where it was made. However, if the wine is brown or tawny, that should give you pause. Brown coloration is a sign of oxidation in both red and white wines of all varieties. However, this is a normal color in aged wines and is actually a sign that the wine has aged well. As a general rule, if the wine is no more than a few years old, it shouldn’t appear tawny or brown at all, but if the wine is a few decades old, this color is a good sign.

Step 3: Smell the Wine

As for smell, your wine’s bouquet will vary depending on the variety, style, and age. For example, it’s not uncommon to smell a slightly funky barnyard note in Côtes du Rhône blends . This is not a serious wine flaw. Instead, it’s caused by Brett and at low or moderate levels is completely normal—even desirable—in these wines. Abnormal smells are those of mold, wet newspaper, wet dog, or vinegar these are signs of a corked wine or a wine that has reached its natural expiration date. Another bad sign is a cooked fruit smell in a very young wine. This aroma typically only develops as a wine ages, so if you’re identifying it in a wine that’s only a year or two old, it is a sign that the wine has been exposed to too much oxygen far too quickly.

Step 4: Try the Wine

Even if you get through this stage and your wine still looks and smells normal, you’re not quite out of the woods yet. It is time to taste the wine. Any wine that tastes very bland or that has a strong vinegar or chemical taste has gone bad in storage. You can spot this easily because you’ll have no desire to take more than one sip of wine. Other red flags are less obvious and unpleasant, but equally problematic. For instance, a dry red wine should never taste sweet, and if it does, it has likely suffered from heat exposure. Still wines should never have carbonation if they do, it’s a sign that the wine has gone through a secondary fermentation in the bottle.

Getting a taste of corked wine or wine with another serious flaw isn’t the most pleasant experience, but it’s unlikely to harm you. You can safely drink wine that’s gone bad in storage—if your taste buds can stand it.

Wine Flaws: Cork Taint and TCA

You've opened a bottle of wine that's supposed to be outstanding. But when you put your nose to the glass, it smells like something you pulled out from a forgotten corner of a damp basement. What's the problem? Most likely it's TCA.

What is it?
TCA stands for 2,4,6-trichloroanisole, a chemical so powerful that even in infinitesimal amounts it can cause musty aromas and flavors in wines. The compound forms through the interaction of plant phenols, chlorine and mold. It most frequently occurs in natural corks (TCA can even form on tree bark) and is transferred to the wine in bottle--which is why wines with these off-aromas are often called "corky." But the taint can originate elsewhere in wineries, where damp surfaces and chlorine-based cleaning products are commonplace barrels, wooden pallets, wood beams and cardboard cases are all sources of phenols. If TCA goes undiscovered, it can spread and eventually taint the wines.

How do I recognize it?
Although TCA taint poses no health concerns for wine drinkers, it can ruin a wine. At higher levels, it makes a wine smell moldy or musty, like cardboard, damp cement or wet newspapers. At its worst, the wine is undrinkable. At lower levels, TCA taint merely strips a wine of its flavor, making normally rich, fruity wines taste dull or muted, without imparting a noticeable defect. This can leave drinkers disappointed in a wine without being able to pinpoint why.

Experts say people vary widely in their ability to perceive TCA in wine, depending on their genetics and experience. Some cork producers claim that levels of 6 or even 10 parts per trillion (ppt) are acceptable, as many people won't notice TCA at this level. However, research in Europe and at the University of California, Davis, indicates that some tasters can detect TCA at 1 ppt to 2 ppt, and a rare few can perceive it at even lower levels. People with higher threshold levels may perceive an off characteristic without being able to identify it.

There is no legal standard for acceptable TCA levels in wine.

How common is it?
As with thresholds of perception, estimates of TCA-taint frequency in wines vary widely. In the past, the number cited ranged from 1 percent to as much as 15 percent of all wines, depending on whether the estimate came from closure manufacturers, vintners or another source. Wine Spectator's Napa office has been tracking the number of "corky" bottles in tastings of California wines since 2005, and the percentage of defective corks in that category has dropped from a high of 9.5 percent in 2007 to a low of 3.7 percent in 2012. The cork industry has a different estimate of cork failure: typically 1 percent to 2 percent.

Are there other causes of "corky" wines?
Yes. When repeated bottles of the same wine, multiple wines or multiple vintages from a winery show the same flaws, the problem is not likely due to a few bad corks. There may be widespread cellar taint.

Many cases of taint are caused by other environmental problems at wineries, such as moldy cellars, antifungal treatments and flame-retardant paints. Like TCA, a compound called 2,4,6-tribromoanisole (TBA) gives off musty, papery aromas it is used in preservatives to treat wood. Contamination from chemically treated woods in renovated cellars plagued many estates in France, particularly in the 1990s. Some properties had to tear down and reconstruct buildings to eradicate the problem.

Corks fight back

19 August 2017 A shorter version of this article is published by the Financial Times.

In the first decade of this century, many were predicting the demise of the cork industry, centred on Portugal, so popular were alternative wine bottle stoppers such as screwcaps and synthetic corks becoming.

The problem was the shockingly high incidence of TCA, the abbreviated name of the compound responsible for the most common sort of cork taint, in natural corks. Until recently all corks were made by punching little cylinders out of strips of cork oak bark, and trying, not always successfully, to keep the process as hygienic as possible. Far too many wines have ended up infected with TCA, either massively, in which case the wine smells undrinkably mouldy, or (worse for wine producers) mildly – in which case drinkers are likely to think it’s the fault of the wine rather than the cork.

Australian and New Zealand wine producers became so frustrated with the poor quality of corks they were sent back in the 1990s that most of them have switched wholesale to screwcaps, which do the job of keeping wine’s enemy, oxygen, out extremely efficiently – initially too efficiently but now most producers have worked out their ideal OTR (oxygen transmission rate) and choose screwcaps they think will allow the right amount of oxygen through the lining of the screwcap to facilitate the wine’s ageing process.

Screwcaps have become so popular for cheaper wines that they are now to be found on about a quarter of all the 18.5 billion bottles of wine that need a stopper each year.

Synthetic corks, the ones made of plastic or, from the market leader Nomacorc, a sugar-cane derivative, are about half as common as screwcaps and are used mainly for less expensive wines in countries such as the US and France, where screwcaps are not widely accepted.

Screwcaps are the cheapest stopper of all, which presumably adds to their popularity with wine bottlers, but I for one admire those producers of superior wine who would rather sacrifice scorn from the odd uneducated consumer in exchange for guaranteed freedom from TCA and 100% consistency in how the wines develop.

Inconsistency of wine evolution has been the other big problem with natural corks, each one of them varying slightly in how much oxygen is available in each bottle. I have had bottles of the same wine from the same case, such as the two halves pictured below, that have been unrecognisably different, one from the other.

At one time it looked as though the cork industry was under threat, but thanks to the rapid growth of bottled wine in both the US and China, the dominant natural cork supplier Amorim of Portugal has seen six consecutive years of sales growth. They report they are now selling two billion more corks a year than they did when screwcaps and synthetic corks started to make a real impact.

One reason why quality-conscious wine producers now look more kindly on corks is that – at long last – guaranteed TCA-free options are available.

One of the two major new wine bottle stoppers currently fighting for business at the top end of the market is Diam, owned by a French company that also owns important coopers Seguin Moreau (and recently bought a more commercial natural cork producer in Portugal). The Diam technical cork was launched in 2005, and from a standing start now sells 1.25 billion stoppers a year, including the Mytik sparkling wine version.

Diam corks don’t look that great. Visually they bear a similarity to the cheap agglo corks made up of lots of little cork particles glued together, but in production method and efficacy they are quite different. I will spare you the intricate detail that so inspires Diam’s team of food technologists, but basically they buy cork from around the world and, at their plant just over the Spanish border from Portugal’s cork country, treat it with supercritical carbon dioxide, the vital element that is somewhere between a gas and a liquid, to eliminate 100% of the volatile molecules that might alter flavour. (There are now other, rival products that guarantee elimination of up to 80% of possible TCA.)

The cork is reduced by 60% of its volume to tiny grains of suberin, the soft, doughy bit of cork bark, and this is then moulded into cylinders with FDA-approved blending agent and microspheres that prolong the life of the cork. The finishing and printing take place all over the world in their finishing centres such as the one they operate jointly with California wine giant Gallo.

The process was initially used in the food and cosmetic industries – the parfumiers of Grasse are able to preserve delicate rose aromas because of it, for example – and the patent for the process as applied to cork is held jointly by Diam and, of all organisations, the French atomic energy authority.

At their plant in Céret near Perpignan (pictured above right it dominates the town's landscape), I was shown the tank below, proudly shown off by Diam's European marketing director Pascal Popelier, full of extracted TCA, which, I was told but found hard to believe, is destined for the cosmetics industry, an anti-ageing cream this time.

All Diam corks are marked Diam somewhere, so, only once you have pulled them, you can tell that your wine was neutrally sealed. I complained to Diam’s head of R&D that Diam stoppers are so inelastic that they are pretty hard to reinsert into a bottle neck (though not as hard as the early synthetic corks). ‘Exactly!’ he beamed. ‘This shows how good they are at their job.’

I’m noticing Diam more and more, and would love the producers who use them to advertise the fact – as of course would those who sell them. They guarantee both 100% removal of TCA and 100% consistency of wine evolution.

Within France, Burgundians have been keener Diam customers than the Bordelais, particularly for their white wines, presumably in the wake of their difficulties with premature oxidation. The Diam team is especially proud of Louis Jadot’s decision to stopper all their grand cru white burgundies with Diam, which comes in several different versions, according to OTR and guaranteed life of the cork – D1 to D30, guaranteed to last 30 years. (Burgundians choose minimum OTR.)

In practice, wine producers tend to trial Diam for their less expensive wines before moving on to use it for the top of the range, which from a consumer’s point of view is a little frustrating. Mytik has become so popular with Prosecco producers that total Diam sales to Italy are likely to overtake those to France this year.

But Portuguese cork producers Amorim and MA Silva now offer natural corks they claim are TCA-free. Amorim launched theirs, ND Tech, at the end of 2015 and expect to sell 50 million of them this year. NDTech (the Diam team, most famous producers of ‘technical corks’, seemed flattered that Amorim chose to append ‘tech’ to the name of this premium product) is quite a different animal from Diam. It is the crème de la crème of their natural corks, subjected to such a rigorous selection process that the company can guarantee that any remaining TCA level will be well below the perception threshold. But the process takes so long that at present it can yield only three corks a minute.

Those already using NDTech, such as Ch La Conseillante in Pomerol, report that they are already enjoying wine evolution that is as consistent as it would be under screwcap.

The following are very rough comparative prices per thousand wine bottle stoppers as charged to a small wine estate.

  • Synthetic corks €70-€250
  • Stelvin screwcap €100 (cheaper alternatives are available)
  • Diam 5 €170
  • Diam 10 €220
  • Top-quality untreated natural cork €300-€400
  • Vino-Lok glass stoppers €450-€1,100
  • NDTech €500 (a similar product is available from MA Silva)

Ken Lamb, a London-based wine lover with a strong business background, sent this particularly pertinent comment:

It has been fascinating to be vice chairman of Vinventions, the holding company for Nomacorc, Ohlinger, Vino-Lok, etc. I visited the R&D team in the south of France a couple of years ago, which is an amazing experience for a wine geek.

Vinventions was established because management assessed the fragmented closure market and the varying needs of winemakers and consumers, and concluded that no single kind of closure is ideal for all wines/circumstances. So, it offers closures made from a variety of polymers, one-piece natural cork, screwcaps and, very soon, SUBR, a combination of TCA-free cork particles (as in Diam) and a natural product-based (corn) neutral polymer.

Diam has its line of micro-agglos also made from similar cork particles and a variety of binders, including Origine using beeswax and other materials as binders.

In my view, the next few years will be an interesting battle of sales and marketing continuing to argue about: (1) OTR issues (particularly consistency in one-piece natural cork and screw cap, when OTR is considered desirable) (2) whether micro-agglos leach anything into wine and whether partly based or full-based polymer closures impact the smell/taste of wine and (3) as ever, cost. I expect that the better driven closures and screw caps will all offer equivalent ease of use, although I'm not sure whether the problem you had with reinsertion will be solved . too soon to tell. At the finer wine end, the ability to use Coravin effectively will have a role for some consumers and, increasingly, restaurants.

Aesthetics across all closures will also be important . printing on screw caps . whether polymer-based and micro-agglos mimic the look of one-piece natural cork or not, etc.

As TCA has become less of an issue with better closures, the issues debated and that are relevant to producers and consumers have changed and also continue to differ dramatically by market. It's a good time to be a wine consumer, as the quality of closures made by the better closure producers has evolved to a very fine level of quality (still, of course, with some issues) in the last decade.

Why You Shouldn’t Sniff the Cork and Other Ridiculous Wine Rituals to Avoid

IT’S COMPLICATED Why can’t wine service be more straightforward? So much of the ceremony around pouring and presenting is no longer practical.

Lettie Teague

I WAS RECENTLY watching a video on how to saber a bottle of Champagne—that is, sweep a blade along the neck to remove the top with a flourish. (Such videos are surprisingly numerous.) I learned that sabering (aka sabrage) dates back to Napoleon’s era and that a kitchen knife can serve as a saber if you happen to be without a sword. I also learned that sabering is extremely dangerous, and you should never saber without wearing glasses or while standing indoors. So why is this risky ritual still relevant now?

Sabering a Champagne bottle may well be an act of “chest-thumping badassery,” as the producer of one sabering video asserted, but I also think it’s outmoded and dumb. What about other silly wine rituals and customs? Should they all go the way of the dodo?

If I could I’d definitely make extinct the silly ritual wherein the waiter or sommelier uncorks the bottle and presents the diner with the cork. This practice originated as a practical one: Long ago when wine bottles didn’t have labels, identifying information was only found on the cork. Today, when both labels and corks identify the wine, presenting diners with the cork so they can make sure the two match can still be a useful exercise—if the diner knows that’s the point. The bottle could be a fraud, for instance, if the vintage on the label doesn’t align with the one on the cork. Such a mismatch could also indicate the producer is not credible or is at least rather lax.

When a wine drinker doesn’t understand the purpose of the ritual, what’s the point? My friend Gabrielle told me she’d always assumed that when she was handed the cork, the “proper” protocol was to sniff it—a common misconception—and she was surprised to learn it was not. Why don’t sommeliers tell people why they are presenting them with the cork? Why do they leave it for the customer to figure out?

Of course, many bottles aren’t sealed by corks at all these days but by screw caps. Do screw caps require a different ritual, or do sommeliers also offer diners the cap to inspect? I put the question to Erik Liedholm, longtime wine director of the John Howie restaurant group in Seattle.