The Champagne cork manufacturing

It is around 500 BC that the liege appears to close amphora in clay. Between the IVth century and the end of the XVIIth century, wines were stored only in casks: It is the discovery of the bottle that will slowly and progressively introduce corks for keeping wine properly. The cork industry was born...

Geography:

The Le liege-oak (in Latin quercus suber) occupies vast territories located west of the Mediterranean valley and on the Atlantic front: it bears climates up to 1400 meters high. It reproduces naturally and reproduces its external layer after harvesting. The appearance of liege starts when the tree is born, however the first outburst of external layer only appears after 15 to 18 years. A new layer of liege starts appearing gradually; this layer is called female liege or reproduction liege and can be harvested every 9 years.

The harvesting:

Stripping of cork or barking is the technical name of the operation of lifting of the liege; it takes place 10 to 12 times in the life of this tree whose longevity is 120 to 150 years. This operation is carried out June at August and requires many care, most significant consisting in practising a circular notch on the trunk without wounding the tree; it is what is called the crown making, then one splits cork in the longitudinal direction with a special hatchet whose edge takes off cork and the handle cut in bevel detaches the bark of the tree completely. The corkboards are then piled up in skirts of forest and will dry for three months approximately. Once dry, they will undergo a first sorting on the spot, the commercial lieges going directly in the factories of preparation. It there that they will be boiled, then is scraped, aimed and classified according to their thickness and their quality.

Components of the stopper with champagne:

The increases in thickness in the corkboard are a function of the nature of the ground and the topography of the terrain; thus, more the tree will push slowly, more the board will be thin and firm. It is of course this type of cork that each manufacturer of stopper seeks to manufacture the stopper with champagne called to contain costs, which costs 5 to 6 atmospheres pressure in the bottle. This ideal cork is boiled second once before being output in strips; those are then spread in plates thickness of the cork disc.

The operation of cutting is then carried out on machines to tube. As for the cork plate perforated, it is crushed to obtain the cork pellet being used for manufacture of the agglomerated part of the stopper or head.

The rough stopper thus consists of two parts: the cork head or handle " agglomerated " (outside the collar of the bottle), the body made of two cork discs " massif " (inside collar of the bottle).

• The moulding: the head is manufactured by hot moulding on an automatic chain starting from a volumetrically proportioned granulated mixture and of adhesive. This process allows a multidirectional compression of the pasted pellet and later on a better blooming of the stopper.
  
• The sticking: once the manufactured handle, it is ground on its faces receives two discs. This work is carried out on semi-automatic machines with drying of the stoppers maintained under individual presses in resistance furnaces electric during 20 minutes to 80.
  At the end of this stage, the stopper was born... but it is still rough.

• The sanding: after several days of rest necessary to drying in heart of the adhesive of the discs, the stopper is sandpapered on its cylinder and its faces in order to obtain a product finished with precise dimensions. Its diameter will vary between 31 and 27 mm and its length between 48 and 44 mm, this according to the interior dimension of the collars of bottles.
• The choice: this operation, undoubtedly most delicate, requires a constant attention and consists in inspecting one by finished stoppers. Those ravel on carpets to choose each one cash two operators, one to inspect the mirror and the other rolls it. Thus, of the million stoppers are selected each year by human eye. An automatic process will difficultly replace it.
• Controls: They intervene front, during and after its manufacture. Controls are carried out with the reception of the raw materials, then under development, with all the stages of making of the stopper, and finally before the shipping by statistical takings.
• Marking: last operation, which consists with stamping each cork. On mirror and rolls, the champagne marks are printed. Once marked, the stoppers either are glossed with the traditional ribbon of paraffin, or treated on all their surface, in a double but: to facilitate the introduction of the stopper into the bottle and its later extraction, and to waterproof its surface to ensure the sealing.

Text are gracesciouly provided by Sagréra
Photographs are gracesciouly provided by