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On the trail for cork.

We had bumped over several kilometers of dirt road somewhere north of Evora in east central Portugal, three hours by paved highway from Lisbon and under an hour from the Spanish border. We were deep inside a mixed cork oak forest. Mixed to the point that we had to wait for a cowherd to drive a herd of cattle out of our way.

"This is where it all starts. This is where we have to begin to apply the quality controls." The man speaking was Carlos Albertos Relvas of Relvas Corticas, one of the world's leading suppliers of sparkling wine corks.

Pointing to the huge stacks of cork oak bark, Relvas noted that they were sitting directly on the ground. "You see, the bottom rows will soak up moisture and it's an open invitation for mold to get into the cork. In a well-maintained forest, the cork would be stacked on pallets, to keep it off the ground," he said.

But it begins even before that. It begins with the harvest, because if the bark isn't cut properly, the tree itself can be killed or the bark can be cut so that future growth is scored by deep cuts, leading to poor quality cork, susceptible to mold and fungus.

The first sorting for quality is actually done in the forest, with some attempt to roughly stack the cork according to thickness and density.

"The farmers are becoming much more aware of the need for good quality," Relvas said. "Because, you see, we will pay more for good quality."

Although cork bark can be harvested every nine years, a premium of up to 40% might be paid for cork 10 or 11 years old because the extra year or two of growth yields a thicker cork. Many farmers in Portugal are facing tough times, because Portuguese farming methods are inefficient compared to the highly-industrialized farms of Germany and the rest of the European Economic Community. Farms that were profitable only a few years ago can no longer support a family. That isn't true, however, of the cork farmers, who can still make a good living on as little as 200 hectares (one HA equals 2.47 acres). The average cork holding now is between 200HA and 1000HA

"Before the revolution," Relvas said, "holdings of 10,000HA were not uncommon."

Relvas said the revolution (which took place in 1974 after the fall of Salazar) did some good things in the cork forests but also created some problems.

"It was good because many of the big landowners didn't care about maintaining the forests. They didn't even live on the land. By splitting the forests up and giving people who knew the forests control, it has become important to them to maintain quality," he said.

There were problems however, because many of the people put in control of the forests didn't know how to harvest properly and many mistakes were made in cutting the bark and taking care of the trees--mistakes that are still being paid for.

But a farmer who harvests good quality cork can gross about 500,000 escudos per hectare (roughly $4,200 at time of writing) on a harvest of 125,000 arroba, a measure of cork equivalent to 15 kilos.

Prices have come down since they peaked in 1989. Cork industry insiders say the prices were inflated that year when the Amorim Group--which controls about 40% of the wine cork market--set out to inflate prices to increase the value of their stock, which was being offered to the public for the first time. For whatever reason, there was a 100% increase in the price of cork in 1989, but it has now come down by over 40%.

Prices of the cork forests were also inflated, with a hectare of mature forest selling for about 500,000 escudos ($4,200) in 1989, compared to about 300,000 escudos presently.

There is extensive planting going forward now, although not as much as Relvas or other forward-looking cork producers would like. The EC is helping finance new planting--since the payback for cork forests is long range. There are EC grants available which pay an annual fee to farmers until the forests come into production, between 25 and 30 years. (Cork oaks live for at least two centuries, but production falls off after about 90 years.)

Another worry to the cork producers was the replacement of the cork oaks with eucalyptus, grown for paper pulp. Eucalyptus is cheap to plant and maintain and a fast cash crop. However, new regulations have come into effect which strictly control the planting of eucalyptus in the cork forest zone.

There is at present about 600,000HA of cork forests, although an exact count is impossible since only about 30% of cork trees are in plantation with the balance in mixed forests.

Many cork producers own forest acreage, but others buy on the spot market. For example, Amorim, the dominant cork producer, owns only about 10% of its own raw cork and buys the rest. Because of Amorim's size, it is able to control the price of cork within certain bounds, much as the muscle of E&J Gallo enables that winery to control grape prices in California.

This has led quality producers like Relvas to begin buying their own forests. Relvas now owns 6000 HA and is shopping for more. Some producers have gone into partnership with foreign firms to buy forest land.

Once the cork is harvested--in the late summer--it is stacked in the forests for six to twelve months for preliminary flattening and drying. The raw bark comes off the tree with a moisture content of 20-22%. After several months of forest aging, the moisture content is down to 14%.

Once the cork reaches the production facilities, traditionally located near Oporto in the north of Portugal, it is boiled to clean it and make it more flexible, then dried again. During this first boiling, no chemicals are used. Large firms such as Amorim use well water to eliminate the possibility of chemicals from treated commercial water. During this drying process, the slabs of cork--roughly 2 feet by 4 feet by about one inch thick--goes through a preliminary sorting for quality. The best cork goes to the wine industry, with lesser grades going for industrial uses such as flooring.

After the cork slabs dry, they are cut into vertical strips the width of a wine cork; corks are punched from each strip with most punching machines operated by foot power or small electric motors and a hand operator. The waste from this punching is sold for industrial use or extruded into agglomerate corks.

After punching, the corks are again graded, with the first sorting often done by machine, the second by hand. Different producers use different standards for grading cork, which is an issue that the U.S. Cork Quality Council is working with the Portuguese to standardize. Since each producer also buys different quality of cork (there are some 600 cork jobbers who buy in the forests and sell to producers) such standardization is necessary.

For example, in the Jose Pereira de Sousa plant in Pacos de Brandao, only the finest raw corks are purchased. So the medium range cork (grades 2 through 4) might be better than the number one grade corks from a plant that wasn't so careful about the raw material.

After grading, the corks are bleached, trimmed and chamfered. It is this bleaching that many in the business believe opens the way for TCA (Trichloranisole) contamination. The bleaching is necessary to remove natural tannins from the cork and to give the cork the light color that many wineries desire. Until very recently, this bleaching was done with chlorine, which seems to react with mold deep inside the cork to facilitate the production of TCA.

Asked why the corks had to be bleached, Antonio Manuel C. Affonso de Barros, executive vice president of Amorim, put it this way: "There is no such thing as a completely natural cork. All corks receive treatment, both necessary treatment and cosmetic treatment.

"Nevertheless," Barros went on, "cork is a natural product, like wine." He advanced the theory, sometimes heard in California, that one reason for the seemingly greater number of cork-tainted wines today was due to the improvement in wine quality. "Before, when wines often had various off-flavors and smells, the tainted corks would be overlooked."

Amorim has set up extensive laboratory facilities for testing, not only for chlorine residue but for other chemicals, required by the European Community.

He hailed the agreement between the U.S. and Portuguese groups as a major step toward establishing standards for cork quality. (See separate story.) "There is a need of constant communication between the wine industry and the cork industry. Too often, we get into a negative relationship with winemakers," he said. "We also need to be talking to glass companies."

Barros insists that even though stronger quality control measures are necessary, he does not feel that plastic closures are a threat, despite repeated efforts over the years by plastics companies to replace cork.

"There are many reasons," he said. "I don't believe people would want to replace a natural product with a synthetic product, which also has some problems. Remember, there is no completely inert closure."

Barros and others agree that the key to block the development of TCA is not to remove all mold from the cork, which is apparently an impossibility, but to remove all traces of chlorine which triggers the formation of TCA when it comes into contact with mold.

There are two possible approaches. First, reduce the moisture content of the cork to discourage the growth of mold and, second, use chlorine sparingly if at all and use drying techniques to get rid of chlorine residue.

Virtually every cork producer visited in Portugal was working on one or both of these approaches.

(It is interesting that in the case of TCA taint in plastic, it is apparently one of the free polymers in plastic which reacts with moisture and mold to produce a taste similar to 'corked' wine. In one well-known case in France in 1990, Evian Water had to recall thousands of cases of product because the water was 'corked' even though, of course, it never came near a cork. In another case, now in the hands of lawyers so of course no one is talking for the record, a leading American brewer is claiming that a large shipment of beer was contaminated with a 'corky' taste by mold which migrated from cardboard shipping boxes through the allegedly completely sealed beer caps and into the beer.)

For example, at Sousa, after an initial burst of high heat, the cork is slowly dried for 24 hours in a wind chamber in order to remove the moisture evenly, as cork dries from the inside to the outside. After 24 hours in the wind chamber, the cork usually comes out with a moisture content or between 7 and 8.5% The standard being discussed would ban the shipment of any cork with a moisture content of over 7.5%. Ten years ago, corks were routinely shipped at 15%. Many U.S. importers such as Bruce Scott at Scott Labs in California is convinced that most TCA contamination takes place during shipment.

At Relvas, corks are bleached in a mixture of acetic acid and S|O.sub.2~ then put into an 18% alcohol solution before being dried to a maximum of 8% by a spinning process. Relvas has also set up a 5,000-bottle test winery as a control measure. If Relvas delivers 100,000 corks, they will use the same batch of corks to bottle 100 bottles of wine. Often, if a problem does develop, they might actually catch it before the cork is used.

Other companies such as Lafitte are using various drying techniques to eliminate the TCA problem. Lafitte, which has a reputation as a supplier of top-grade corks, has also taken a leading roll in the production of agglomerate corks. Curt Goodsill, vice president and general manager of Lafitte, said the company became interested in the agglomerate or composite corks when the price of waste cork material dropped.

"Our niche has always been the boutique end of the business, but we realized we could supply other niches as well," he said. Goodsill said there was a lot of interest in California in the agglomerate corks for wines priced in the $3 to $6 range. The agglomerates sell well in France for less expensive wines.

The cost of the agglomerate cork is about half that of a medium quality regular cork or about $50-$55 per thousand, if no end caps are used. There are industry observers who feel that more agglomerate corks could be used and used without end caps if bottles were shipped neck up, so the cork did not come into contact with the wine. Some California wineries have gone to this shipment method for inexpensive bottlings. Since the cork has very little contact with the wine when shipped neck up, problems of corked wine are virtually eliminated.

It is possible, however, that some cork companies would be less than enthusiastic about selling the agglomerate corks, since every agglomerate cork sold is one more expensive cork not sold.

Besides efforts by individual companies to maintain and improve cork quality, the Portuguese Cork Association is funding a major research center which is now open near Oporto.

Bruce Scott, of Scott Labs, believes the future for natural cork is oriented toward quality cork production.

"What we are seeing is that more and more producers are moving in the direction of Sousa and even the giant producers are realizing that quality is the key to survival. The economic squeeze in Portugal is on the mid-sized producer, the producer who can't afford to modernize. The mom-and-pop producer will survive by selling product to the big producers and everyone will benefit with an emphasis on quality."

Historic Cork Agreement

In an historic agreement reached over dinner at a beach hotel south of Oporto, Portugal, representatives of the Cork Quality Council of California and the Portugal Cork Association agreed to pool their resources to work together in an effort to ensure quality control in the cork industry.

Leading representatives of the California industry, such as Bruce Scott of Scott Labs and Curt Goodsill of Lafitte Cork and Capsule, met with leaders of the Portuguese industry such as Amerigo Amorim of the Amorim Group, the dominant Portuguese cork producer.

Although the two groups will maintain separate identity and agendas, it was clear to an observer at the dinner last fall that those present were intent on fighting back against efforts by the plastics industry to substitute plastic/vinyl stoppers for natural corks for closing wine bottles. Reacting to news stories reporting as much as five to eight percent of bottled wine being ruined by corks tainted with a mold called trichloroanisole (TCA), California cork importers and suppliers formed the Cork Quality Council (CQC) last summer, a group representing about 75 percent of all the wine corks sold in the US.

The CQC, recognizing that a problem with tainted corks does exist (although they would put the percentage of tainted corks at perhaps two to three %) found the Portuguese group anxious to take part in the quality control effort and, indeed, in some cases, taking the lead in dealing with the problem at the source--in the cork forests and processing plants of Portugal.

It is obvious that both California and Portugal take the threat of the plastic closures for wine quite seriously. Several wineries in California have already begun extensive experiments with plastic stoppers and early results have been encouraging to the plastic industry, although it will be several years before the long term effects of plastic stoppers on wine can be evaluated.

Members of the California Cork Council include: Cork Supply International, Inc, Lafitte Cork & Capsule, Inc., Scott Laboratories, Inc., Latchford Package Co., fp Portocork, Inc., Cork Associates and italcork, Inc.
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Title Annotation:includes related article; cork oaks for the wine industry
Author:Walker, Larry
Publication:Wines & Vines
Date:Jan 1, 1993
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