Historically speaking, Cork is mentioned the first time in approx. 4500 BC in Egypt as being used to make buoys for fishing. Greeks and Romans used corks as stoppers for pottery vessels. Following the development of the glass bottle in the 18th century, the cork soon triumphs as the bottle closure of choice.
Cork Oak (Quercus suber)
The cork oak is an evergreen, indigenous to the western Mediterranean region. About 50 % of cork production worldwide comes from Portugal (736.000 ha), another 30 % from Spain, 6 % from Morocco and Algeria, 6 % from Tunesia and the remainder from Sardinia and southern France.
Cork bark can be stripped for the first time, only after about 25 years. This initial "virgin bark" as well as the product of the second stripping are not yet able to be used for wine bottle corks. This means that only after about 40 years, the bark can be used for the first time, for making wine bottle corks. Later stripping is done in intervals of 9 to 12 years. The cork oak tree has a life expectancy of 150 to 200 years. This means that its bark can be stripped about 16 times.
From one ton of high-quality cork wood approximately 300 kilos of cork stoppers are produced, while the remainder is "waste" which is used for manufacturing pressed cork and industrial cork (flooring, gaskets, insulation etc.).
The production of "cork stoppers"
After a long period of storage in the cork forest, the cork sheets are brought to production facilities where they are dried outdoors for at least six months.
The cork sheets are then boiled for about 90 minutes. The extensive sheets are now malleable and various mineral substances and tannins have been washed out.
After drying for some days inside the storrage the sheets are sorted according to thickness and quality and are then cut into strips.
Corks of differing lengths (e.g. 38, 45, 49 or 54 mm) are punched out of the strips, either by hand or by machine. The unfinished corks are then washed and bleached (in the past with chlorine, but now hydrogen peroxide).
In following, an average of 9 electronic and manual sorting processes take place, separating corks into various quality grades. The bleached and sorted unfinished corks are then exported to finishing facilities situated in the country of final product use.
Storrage of raw material
Cork grows in a Mediterranean clima — and evolves its excellent characteristics only at same conditions. This is the reason why we store our raw material in a specialized storage here in Vienna which is completely air-conditioned. The storage conditions for natural stoppers are welled adjusted: +21°C, ca. 50% humidity, in summer- and winter-time. The observation of the parameters, temperature and humidity is controlled continuously from the quality-management.
This storage is a component of the hygienical zone and is controlled under the foodstuffs-standard. High active air-filters avoid an penetration and spreading of dust or microbiological pollution. Materials like wood or carton is being banished from this storage as well as possible. The storraging of the stoppers are on PVC-palettes. Continuous TCA-Screenings and external microbiological monitoring assures a maximum of cleanness and product safety.
Preparation of clichées
To quickly fulfill our client´s wishes, we produce the clichés ourselves in our fotolaboratory.
Therefore we can reduce the time between getting the artwork of a cliché and its finalisation to a minimum.
As soon as the cliché is ready, we can print stoppers until to a maximum amount of 300.000 pieces per day on our different printing-machines.
The printing department and all other further departments are permanently controlled in order to guarantee a high quality product in the end.
After a drying-phase of at least 24 hours in which the ink-printing can stabilize on the stoppers, the product is ready for further preparation.
Two separate product-lines guarantees a continuous treatment of the stoppers without interrupting the production-process. During this process the stoppers will be dedusted three times, so that we can assure an almost 100% dedusted product.
After an careful made end-control of the goods (according to the guidelines of "Geisenheim") by the quality-lab, the stoppers are going to the packing machines and are packed sterilized by 500 or 1.000 pieces. This gives our clients the assurance, that they can store the stoppers with guarantee for 6 months, without any possibility of taking place by microbiological variances.