The Production Process.

The removal of the cork oak bark can only be done by experts, the descortiçadores, in order not to damage the tree. The process consists of six steps and two men are needed for each tree.

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After harvesting, the cork is stabilized for a minimum period of six months before beginning its industrial processing. This allows the moisture present in the cork to become uniform. The planks are stacked on large surfaces of concrete or other permitted materials, with a slight incline, to prevent microbiological contamination and maximize air circulation.

The first step of the cork processing is boiling. The cork planks are piled in clean water for at least one hour in order to clean the cork, extract water-soluble substances, and make it softer and more elastic.
This process allows the gas contained in cork cells to expand and thus, its structure becomes more regular and its volume increases by about 20%.

After boiling, the cork goes through yet another stabilisation period. This process lasts from two to three weeks and serves to flatten the planks while allowing them to rest.

After the cork is stabilized, knowledgeable technicians categorize the planks based on their thickness, porosity and appearance.
The thicker ones are used to produce the natural cork stoppers, while the thinner and rougher ones are used to manufacture technical stoppers.

After being selected, the cork planks fit for the production of natural cork stoppers are cut into strips with a width slightly greater than the length of the corks to be manufactured.

Punching is the name of the process of perforating the strips of cork with a drill. This results in a perfectly cylindrical stopper obtained directly from the cork plank.
All the waste from the punching stage is later ground up and reused as cork granulate for technical stoppers.

This operation is designed to separate the finished stoppers into different grades, which are determined by automatic scanning of their surface.
In some cases, selection is carried out visually and manually, relying on the human eye. During this phase, in addition to establishing quality classes, defective stoppers are eliminated.

The stoppers are washed after rectification in order to clean and disinfect the stoppers.
After washing/disinfection, the moisture content of the stoppers is stabilised, ensuring optimal sealing performance while simultaneously reducing microbiological contamination.

When corks present high levels of porosity, they may be colmated. Colmation consists in sealing the pores on the surface of cork stoppers (lenticels) with a mixture of cork dust obtained from the correction of natural cork stoppers.
In order to fix the dust in the pores (lenticels), a food-grade glue is used. This process is used to improve the visual aspect of the stopper and its performance.

After boiling, the two rougher sides of the cork planks are removed in order to obtain soft, uniform sheets of cork with a thickness of around 6.5 mm.
These sheets are mechanically punched in circles – discs the size of the ends of the stoppers to be manufactured.

The bodies of technical stoppers are formed by granules obtained from the by-product of high quality cork products and punching of natural cork stoppers.
These by-products are transformed into granules of different sizes by grinding machines. These granules are then agglomerated using food-grade glue, and the bodies are individually moulded.

The discs and agglomerated bodies are fed into assembly machines. The discs pass in front of cameras which select the side of the disc that will come into contact with the wine.
A mark is printed by the machine on the opposite side of the stopper. This mark is detected by a camera in the assembly machine, indicating that this is the side to be glued to the stopper body. The discs are glued to the end of the agglomerated cork cylinder using food-grade glue.

The assembled stopper is dried in order to ensure that the glue is completely dry, after which it moves to the rectification stage. Here, as for natural stoppers, the stoppers are corrected in order to give them the required dimensions. The washing, sorting, finishing and packaging processes are, from this point, similar to those for natural cork stoppers.