Definition: corking (types of)

Cardboard packaging: capacity: 5,000 corks - Made from eco-friendly recycled paper(Testliner) - Protective barrier against dirt, dust and moisture - These cartons are lacquer-free - They are fully recyclable in accordance with Resy requirements (in Germany, the RESY organisation is responsible for the recovery and recycling of cardboard packaging waste).

The 20 steps involved in producing a high-quality cork stopper:

1. Selection criteria and purchase of cork from selected forest areas.

2. Storage and stabilisation of cork (in the forest or at the factory) for a minimum of 8 months in "stacks" exposed to the air.

3. Boiling, with automatic water renewal (removal of tannins, mineral salts, impurities and insects).

4. Stabilisation of the planks for 2 weeks: as its volume increases, the cork becomes more elastic and malleable, ready to be worked.

5. Sorting of raw planks: selection of cork (7 thicknesses and 7 qualities).

6. Cutting of strips, their width corresponding to the length of the cork.

7. Tubing of the corks: the strips are perforated with a punch, cork by cork, as close as possible to the inside (crumb).

8. Preliminary sorting, elimination of waste and corks with major defects.

9. Dimensional correction of the corks after moisture stabilisation.

10. Thorough washing and disinfection, neutralisation in an acidic pH bath and thorough rinsing with pure water. Removal of surface water by centrifugation immediately after rinsing.

11. Thorough drying in a specific room so that the corks reach the desired moisture content.

12. Sorting to obtain uniform quality. Initial sorting is carried out by electronic camera-equipped machines; final sorting is done on conveyor belts by specialised workers.

13. Counting of caps by machine and identification of batches for traceability purposes.

14. Quality control before shipment (physical, chemical, biological and organoleptic analyses); issuance of the corresponding quality certificate.

15. Direct transport to Switzerland by lorry in accordance with the specifications.

16. Quality control upon receipt of the batch in Switzerland. Acceptance of the batch in accordance with the specifications.

17. Customised marking with food-grade inks; air drying.

18. Dust removal by vacuum before applying surface treatments. Lubrication of caps in accordance with food industry standards.

19. Final quality control to establish the Chaillot declaration of conformity, in accordance with the relevant internal procedures.

20. Packaging in barrier bags suitable for food product requirements, designed to protect against dust, moisture and odours. Preservation of the cap's qualities using inert gas.

In these 20 steps, 7 critical points have been identified and analysed in relation to the potential food risks that may arise during the manufacture of the food stopper.

According to Péchiney-Capsules,the screw cap is one of cork's competitors that has been around since the 1970s. Continuous improvements have made it increasingly effective. Another "plus" for the Stelvin® cap. Péchiney-Capsules' wide range of expertise has enabled it to develop a new Stelvin+® cap offering higher print quality combined with the elegance of stamped caps: an even more opaque, deep and uniform background colour allowing for a variety of effects, a covering skirt decoration and a richer colour palette, and an inked relief on the head. Greater flexibility: thanks to flexible equipment and organisation, the Stelvin+® cap is also suitable for small production runs. The Stelvin+® cap offers the same advantages as the Stelvin® cap: it preserves the qualities of the wine thanks to a perfect liquid seal, controlled gas exchange regulation and the absence of TCA (cork taint) - the practicality of the bottle is improved by easy opening and re-closing - standing, lying down or upside down, the bottle can be stored and transported in any position - two sealing options are available: Saran film, which is completely airtight, and Saranex 38, which promotes exchange similar to cork - standard bottle, with standard BVS glass ring - capping operation identical to that of a Stelvin® cap - 30x60mm calibre. The Swiss market was the first to widely adopt this concept in 1988. In 2001, Australia and New Zealand began to opt for screw caps for both their white and red wines. 2002 was the year of confirmation for New World countries, including the USA. France and Germany also joined the movement.

Source: Pechiney-Capsules.

Vitisphere - News - Interviews - 16/09/2004

Interview: André Lurton, Bordeaux winegrower and producer.

For André Lurton's vineyards, the time has come to "loosen the screw on the capsule". André Lurton explains the benefits of taking the plunge and switching to this alternative to cork, even for grand cru wines.

At the last tasting and presentation of en primeur wines in April, you presented two of your 2003 white wines with screw caps. This is a first in Bordeaux. Why such a revolution, especially with grands crus?

The quality of our wines is our sole motivation. The essential quality of the screw cap is that it is impervious to oxygen, the number one enemy of white wine. In my opinion, it is therefore essential for white wines suitable for ageing, and especially for fine white wines such as Couhins-Lurton and La Louvière. In fact, we did not hesitate to take the plunge and offer our customers wines sealed with screw caps.

What are the advantages of STELVIN screw caps?

The perfect seal and total neutrality of the seal in contact with the wine are the main advantages of screw caps. But they are also easy to open, which is important as some consumers abroad are not familiar with the use of a corkscrew. With screw caps, you can also reseal a partially consumed bottle. Finally, bottles can be stored upright without the risk of the cork drying out, which means no more risks in supermarkets. It should also be noted that until recent years, screw caps were poorly received by consumers. They had a "low-end" image, but today's caps are well presented with high-quality printing. The bottles are elegant.

Are there any other wines besides Couhins-Lurton and La Louvière that use screw caps?

Yes, our Château Bonnet in Entre-deux-mers is already available to our customers with screw caps, particularly in the Nordic countries, Canada, Switzerland and the USA. We will gradually offer the 1.5 million bottles of white wine we produce with this type of closure. It is very important and essential that this wine, which we have spent over a year developing, arrives in the best possible condition on our customers' tables. Our sole aim is to satisfy them by offering them the best quality. Screw caps perfectly meet our requirements in this respect, as they preserve the aromas, freshness and fruitiness of the wine while offering excellent natural ageing. This type of closure is likely to become more widespread than imitation corks. We are currently conducting trials with caps that are slightly permeable to oxygen for sealing red wines.

What were the initial reactions from opinion leaders?

In April, the Couhins-Lurton and La Louvière white wines, sealed with screw caps, were presented at the Union des Grands Crus en primeur tastings. This allowed us to gauge the reactions of the tasters. Overall, to our surprise, they were very positive. Of course, there are always those who are hesitant, but we need to take the time to explain it to them, and that is our job. Indeed, only knowledge advances the world, not ignorance. We need to educate people, and then the message will naturally get through. Let's try to accept that this is an evolution, not a revolution.

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When synthetic corks first appeared, critics told us that they were a fad that would not last. However, Supreme Corq, Inc., based in Kent, Washington, which began producing synthetic corks in 1992, seems to have proven the naysayers wrong. The company currently produces more than 100 million customised synthetic corks (2004), made from food-grade thermoplastic elastomers, sometimes in bright colours, for more than 1,000 wineries in 30 different countries. In fact, Supreme Corq is the world's largest manufacturer of synthetic corks. Robert L. Anderson, President and Chief Executive Officer of Supreme Corq, recently spoke with Market Watch about the controversy surrounding synthetic corks.

Q: While many believe that synthetic corks reduce wine spoilage and oxidation, many still criticise their use for prestigious wines. Why is that?

Anderson: In an industry as steeped in tradition as wine, change takes a long time. Before the advent of screw caps in the late 1960s, there had been no viable alternative for sealing wine and spirits bottles since the^mid-17th century. Today, wineries use and accept synthetic closures for wines of varying prices. We have customers all over the world who use our synthetic closures on bottles ranging from £5 to £100 each.

Q: What is Supreme Corq doing to change attitudes?

Anderson: A global market study we conducted indicates that an increasing number of consumers are willing to accept synthetic closures. Corks are generally an accessory item for consumers. When they want to taste a wine, they usually trust the producer to choose the appropriate closure. So we organise seminars with potential customers. We also work with leading research institutes and laboratories around the world to write articles and presentations for forums and conferences. In addition, I am currently participating in a postgraduate programme on wine at the Bordeaux Business School, with the aim of better understanding the French market.

Q: Do you think that alternative closure systems, particularly synthetic corks and screw caps, will prevail over traditional cork closures?

Anderson: Given the increase in global wine production, there is enough room in the market for several closure options, including cork, natural-type closures, synthetic closures and screw caps. Technological advances have given producers the opportunity to choose between several types of closures, which was not the case ten years ago. Ultimately, producers want to produce wine of consistent quality, and in this regard, they will choose the closure system that is best suited to achieving this goal.

Q: If I say to you: Synthetic corks destroy the romance of wine.

Anderson: I would say that's nonsense! Synthetic corks preserve all the ritual associated with removing the "cork," and consumers still get to enjoy the inevitable "pop." Above all, synthetic corks allow consumers to enjoy wine of consistent quality, without trichloroanisole (TCA) [which gives wine a "mouldy" taste]. After all, there is nothing romantic about opening a bottle of wine that tastes like cork and is undrinkable.

Interview with Robert L. Anderson of Supreme Corq Inc - 1997-2002 Market Watch, January/February 2003.

The latest innovation in closures is a glass stopper to replace cork. The multinational aluminium company Alcoa (European headquarters in Geneva) is launching a new wine bottle closure system. Will we finally be freed from the taste of cork?

This new wine bottle closure is a glass stopper that fits into the neck of the bottle and is held in place by a toric seal and an aluminium cap. The product will be launched on the market in early 2005, but some Swiss winegrowers and winemakers have already had the opportunity to try it out this summer. The Vino-Lok, as it is called, has one decisive advantage: it can be removed by hand, without the need for any tools. Its price, between 45 and 60 centimes per piece (including the cap), is similar to that of its high-quality cork counterpart. This is why Alcoa Germany, where it is manufactured, is targeting customers who produce high-end wines.

In recent years, increased cork production has led to a decline in the quality of traditional corks. The multinational company developed this system, which is similar to a carafe stopper and is kept watertight by its removable aluminium cap, to offer winemakers an elegant alternative. This spring, Vino-Lok won the gold medal for innovation at the German trade fair Interventis Interfructa. Since then, the product has been tested by around 40 winemakers in several regions around the world, as well as by oenologists from the Technical University of Geisenheim and the Oppenheim Research Institute. Elegant, recyclable, practical, reusable and odourless, this product represents a minor revolution in the world of wine. Although no technical drawbacks have been identified so far, some professionals have expressed scepticism due to its total airtightness.

High-end specialists in France believe that cork will be difficult to replace because its natural properties allow gas exchange between the air and the wine. This is not possible with Vino-Lok. However, trials have proved conclusive and, by mid-2004, nearly 70 wineries had already ordered the product, representing half of the multinational's target figure.

ALCOA has no intention of replacing the traditional cork: knowing that between 15 and 17 billion bottles are sold worldwide each year and that this figure is likely to reach 22 billion by 2010, it is targeting a share of this market. Alcoa is aiming to sell around 15 million Vino-Loks per year. The product has great potential in Switzerland, as the country has traditionally been interested in alternative closures, as was the case with screw caps. Vino-Lok will be mass-produced in Germany at Alcoa's plant in Worms from autumn 2004. It remains to be seen whether, culturally, it will appeal to wine lovers. It is true that this closure somewhat disrupts the tradition surrounding a good wine, both in terms of the materiality of the cork and the ritual of opening the bottle. It is precisely this ease of use that, according to him, has won over his first customers. Lufthansa, for example, has chosen to adopt it because it will make life easier for flight attendants.

Among the Swiss winemakers approached by the multinational, the conclusion is that a high-end wine can never do without the traditional cork. However, Vino-Lok is of interest for everyday wines, for which screw caps are currently used. This represents about 10% of its production. As glass does not have the flexibility of cork, winemakers who opt for Vino-Lok must ensure that their bottles have a uniform neck diameter. The market share of this new system is therefore likely to be fairly low for the time being. At Alcoa, which has invested between €4 and €5 million in the operation, this innovation accounts for 2% of global bottle production, which is already a good result.

The elegance of glass is therefore not quite ready to dethrone the rusticity of cork, even if it is beginning to intrigue winemakers.

Conclusions according to the Revue des Œnologues - Comparative study of the performance of different types of closures - (excerpt) The wine industry makes extensive use of cork or cork-based closures to seal wine bottles. New closures have appeared on the market in recent years, but there are no objective studies available to assess their technical performance. In this study, through an experiment involving the storage of corked wines under real conditions, the characteristics of different types of closures available on the market were compared (natural cork (2), sealed cork (1), composite 1+1 (1), cork-based synthetics (2), plastic synthetics (3)). The evolution of extraction forces and closure quality was measured after 6 and 12 months of storage in two positions (upright and horizontal). The evolution of exogenous antioxidants in the wine made it possible to assess the oxidative phenomena in the bottle. Finally, sensory analysis and the measurement of various migrant compounds (volatile and semi-volatile) made it possible to estimate the chemical and organoleptic inertia of the various closures studied. The physical quality of the closure appears satisfactory in the vast majority of cases. However, high extraction forces are sometimes observed with certain synthetic closures. One of the synthetic cork-based closures has poor oxidation stability. Synthetic plastic closures perform better, but their performance is generally inferior to that of natural cork. In terms of chemical and organoleptic inertia, the colmated cork and one of the cork-based synthetics imparted a bad "mouldy" taste to some bottles due to the diffusion of 2,4,6-trichloroanisole into the wines. Synthetic cork-based stoppers introduce numerous volatile and semi-volatile compounds from the agglomeration formulas; plastic stoppers also introduce compounds that are not normally found in wine. The nature and quantity of the migrants listed vary depending on the type of stopper considered. Compared to natural cork, the chemical inertness of these stoppers is therefore far from perfect. On the other hand, none of the molecules reported appear to be capable of directly imparting bad tastes or odours. One of the synthetic plastic stoppers showed residues of undesirable solvents such as p-xylene. In all cases, natural cork stoppers and the 1+1 composite performed best.