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Technological innovation

So the cork doesn't spoil the wine


The disappearance of cork production would hit many jobs and SMEs in the often poorer southern regions of the EU.

Many corks undergo microbiological and chemical changes which impair the quality - or even the safety - of wines and spirits, with the danger that natural cork could be progressively replaced by synthetic substitutes. A European research project has patented an innovative new process which looks set to remove the threat.

The wine industry estimates the financial losses due to the chemico-microbiological deterioration of natural cork stoppers at more than 500 million euros a year. So it is small wonder that the industry is beginning to look for alternative synthetic solutions. "Research by the cork industry over the past 30 years has lacked any clarity of vision or genuine innovation. We have sought to make up for this deficiency," explains Dr Jens Jaeger of the Neustadt (Germany) Institute of Phytomedicine and coordinator of a CRAFT cooperative research project in this field. [1]

Upstream research

In 1997, three cork-producing firms - Juvenal (Portugal), Oller (Spain) and Ohlinger and Buerklin (Germany) - decided to pool their efforts in order to find out why approximately 4% of corks - 500 million every year- seriously spoil the quality of the contents they are supposed to seal. First they analysed the upstream processes, and the way in which the cork sheets are left to stand a while in a warehouse to begin with and then boiled. The corks are produced from a combination of pure cork rings and a mix of compressed granules which are glued together. They are then chamfered, marked and waxed. At each stage in the production process there is the possibility of contamination by chemicals or micro-organisms.

"The poor quality of the water absorbed by the cork during washing, particularly in southern Europe, explains most of toxic - or even carcinogenic - chlorides present. In addition, some of the glue ingredients, such as tetrahydronaphthalene, have been shown to be responsible for changes to aromas, and also the disintegration and permeability of certain corks."

An age-old tradition: could popping the plastic stopper on a fine champagne ever be quite the same?

A patented innovation

Despite the efforts made in terms of water purification, glue quality and the speed of drying after gluing, the only way to significantly reduce the presence of such micro-organisms is to radically change present production processes. The partners therefore studied a new production method which is free of any unwanted ecological, toxic or sensory effects.

"We showed that initially exposing all the raw materials to microwaves effectively kills the micro-organisms. Better still, it substantially reduces chemical contamination."

This technology was recently patented and is to be integrated in the Portuguese and Spanish partners' production lines. "We have presented this innovation to French, German, Hungarian, Australian, Chilean, Argentinean and American wine producers. The response has been very positive. The first corks produced using this technology should be available next spring. It should not only save the cork-producing companies but boost their growth. The interest expressed by the principal customers opens up the prospect of further research."

[1] Supported by the Brite-EuRam programme (Fourth Framework Programme).

Jens P. Jaeger
Tel.: + 49 63 21671328
Fax: + 49 63 21671222


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