Richard Carleton Hacker

PHOTO #1714 – Richard Carleton Hacker inspects a harvested cork tree – the season is June through August - in the forests of southern Portugal, which is also home to the endangered Iberian Lynx – another reason for strict government regulation of cork trees.

Every night a subtle drama plays out in every on-premise establishment that serves wine by the bottle.  It is that “moment of truth,” when the bottle is uncorked, a splash of wine is poured, and the customer does the swirl-sniff-sip routine.  It is then that he or she will hopefully nod approvingly, and the rest of the wine will be poured into waiting glasses.

But unfortunately for the restaurateur, the customer, and the wine industry, once in a great while – five to ten per cent of the time, depending on whose statistics you believe – the customer will look disapprovingly into the glass and mutter something like, “This wine tastes terrible!”  Knowledgeable oenologists might even say, “This wine is corked,” but most wine drinkers do not know what “corked” wine is.  They may simply assume it is a bad year or a bad wine.  Either assumption may be true, and any waiter or sommelier worth his tip will immediately replace the bottle with another – usually a different label or vintage – but the damage has been done and the result is a often a very unfavorable impression of the restaurant, the winemaker, or both. 

PHOTO # 0392 – The final destination of Portuguese corks – atop bottles of Bollinger La Grande Année 1997 and Laurent-Perrier Cuvee Rose Brut, as presented by Master Sommelier Robert Smith at Bellagio’s Picasso Restaurant in Las Vegas.

The Real Culprit

Of course, the real culprit is TCA – not the Texas Culinary Academy - but rather, a micro-organism formed by mold and known more formally as trichloroanisole.   And it doesn’t take much of it to ruin an entire bottle of wine – or a winery’s reputation.

“Even a nanogram can do it,” says Carlos de Jesus, Director of Marketing & Communications for Amorim, a Portuguese cork-making conglomerate that has spent 43 million Euros (approximately $56,000,000) so far on TCA eradication. “To put that into perspective, a nanogram is equivalent to a few seconds in 3,200 years.  

“But the problem is not with the cork,” de Jesus continued, “but with the handling of it. In fact, it is more likely that the wine can contaminate the cork rather than the other way around.”

While some may raise an eyebrow to this, the facts have been born out by extensive research on the part of cork’s biggest champion, APCOR, which stands for the Associação Portuguesa da Cortiça (Portuguese Cork Association), an organization comprised of almost 300 cork producers representing 85% of Portugal’s cork industry.  Founded in 1956, APCOR celebrates its 50th anniversary this year, which is notable because up until fairly recently, TCA was indeed a problem with “corked” wines.  But working closely with Portugal’s Cork Technology Center CTCOR and the government’s Filcork organization, APCOR has practically eradicated TCA in Portuguese wine corks.  And yet, the specter of tainted wine persists.  But the guilty party is no longer cork, as evidenced by the fact that TCA has also shown up in beer.  In addition, one Napa winery was able to trace TCA to contaminated cellars and barrels.

In that case, the real culprit was TBA, or tribromoanisole, a similar mold but one that is more commonly found in wood and plastics than wine corks. Unlike TCA, which has a sulfuric sour taste, TBA has a sweet rancid smell; both are reminiscent of wet laundry.  But even though scientific fingers now point to TBA as another source of tainted wines, the answer for many wineries was to switch to Stelvin screwcaps or ROPP (Roll-on Pilfer-Proof) closures.  “But even screwcaps can harbor TCA” de Jesus notes.   Another solution was the Vino-Lok from Alcoa, which features a glass stopper enclosed in a plastic membrane; plastic, of course, can harbor TCA, as can cardboard, which is used for wine cartons.

PHOOTO #1752 – At Subercentro one million corks are produced on each shift.  These corks are ready to be graded by quality and size.

A Visit to Portugal

PHOTO #0424 -  At a dinner hosted by the APCOR Cork Quality Control Council – influential R&D technicians who consistently improve industry cork standards – Richard Carleton Hacker (r) discusses Portuguese wines and corks with António Rios de Amorim (l), APCOR president and Chairman & CEO of Corticiera Amorim.

But to make sure that cork was no longer the prime suspect in TCA contamination, I visited Portugal and followed a typical wine cork, from its harvest in oak forests in the southern province of Alentejo to its manufacture outside of Lisbon to its shipment to the export facilities near Oporto in the north.

Today, thanks largely to APCOR’s efforts, and working closely with the Portuguese government, the manufacture of Portuguese wine cork is one of the most heavily regulated industries in the world.  You cannot cut the cork bark from a tree until it is at least 25 years old, after which it can only be harvested in nine-year cycles.  But it is not until the third harvest – when the tree is a minimum of 43 years old - that the cork will be of sufficient quality for wine.  “This is not an industry for you to get rich,” goes an old saying.  “It is an industry for your grandchildren to get rich.” 

Once harvested by specially trained workers, the stripped cork is brought to drying yards and carefully stacked, outer bark up, to season a minimum of six months.  After that, it is boiled and sterilized for one hour in “pressure cooker” water tanks heated to 253 degrees Fahrenheit, or just above the boiling point of water, which is 212 degrees.  The planks are then air dried for three weeks before being trimmed and sorted.   Only the top 2% are selected for wine corks.  These premium corks are cut into strips, and the corks are both manually and automatically punched out and trimmed.  They are then polished and sorted by size. Each cork is then optically inspected and scanned for imperfections and any remaining traces of TCA, which appears as a green or yellow blemish (the TCA inspection continues at every stage of the operation).  Next the corks are washed and disinfected with hydrogen peroxide.  APCOR has instituted even newer methods with ozone and microwaves.  Then the corks are dried in ovens slowly, so as not to change their molecular structure, and as a further barrier against microbe contamination.  Finally, each cork is “branded” with a winery name, given a final sanitizing with sulfur dioxide gas, and sealed in airtight bags for shipment.

The Pro Cork Agenda

“The entire cork industry takes 34 years to make what one aluminum screw cap producer makes in one year,” says de Jesus.  “Yet even screwcaps can harbor TCA.  In fact, if we could eradicate TCA from all the corks in the world, we still would not eradicate TCA from the world, because there are other readily available sources of TCA.  So if you think that if you move away from corks and move into plastic stoppers, let’s say, you still end up not solving the TCA problem.  So let screwcaps and glass stoppers stay around, because they (as competition) keep us on our toes.”

I will admit that screwcaps are easier to open, but they do not have the cache of cork.  Nor do they have the porosity of cork necessary for long-term aging of wine.  So until they start making platinum screwcaps worthy of premium vintages, or can inplant screwcaps with microchips that give an audible “pop” when opened, I’ll stick with cork.  Besides, I don’t want to get Mother Nature mad.

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