How is cork is manufactured
After the three-week resting period in the warehouse, the trimmed planks are sliced into strips and cork stoppers are punched out. After punching, the ends of each raw cork stopper are cut to size and polished. Suitable leftover cork pieces are processed into agglomerated corks. Agglomerated cork stoppers – made from compressed cork granules – receive the same care and attention to detail as one-piece corks. Unused cork and even cork dust is processed into other cork products such as insulation and construction materials. Nothing from the cork tree is wasted.
The cork stoppers are then scanned to eliminate imperfections detrimental to bottling. The grading procedure assigns each cork stopper a visual level.
This inspection is done with automated optical scanners programmed to select corks on the basis of pattern recognition. Another procedure is to use highly skilled personnel who visually inspect each cork to determine its visual grade.
Treating the stoppers
The selected cork stoppers then undergo the washing and disinfection process. The most common method is washing the cork stoppers in a watery solution of hydrogen peroxide. Besides washing, the cork stoppers also go through new, additional treatment methods such as using microwaves or ozone to disinfect them .
The next stage is drying the cork stoppers in special stoves. When the moisture levels are lowered and stabilized below 7%, stopper performance is maximized and microbial contamination is minimized.
These methods allow for the stabilization of cork without any change or damage to the cell structure, providing yet another barrier to microbial contamination.
After the final selection, the cork stoppers may be printed according to clients' specifications via roller marking, ink marking or traditional branding.
After branding, they are given a final coating of paraffin or silicone to make them easier to insert and extract from the bottles, while at the same time improving their sealing capacity.
Finally, corks are automatically counted, sanitized with sulphur dioxide gas and sealed in gas-barrier bags.