From bark to bottle: cork’s journey

For three months of the year, the “montados”, or Portuguese cork forests, are hives of activity as teams harvest the bark of the cork oak, quercus suber. Each tree can only be harvested every nine years and it takes 25 years before a tree is ready for its first harvest. Even then, it will not produce the quality needed for a wine stopper until its third harvest.

The harvested bark is then loaded onto tractors and taken to the factory for processing. The growing number of FSC-accredited forests today plays an important role in the fight against TCA, or cork taint, much of which derives from the chemicals that used to be sprayed in the montados.

 The cork bark will then spend around nine months drying in the factory yard. This display shows some of the different thickness gradings (left) as well as faults (right), from ant damage to cracks and mould, which employees are trained to look out for.

The first mechanical process undergone by the cork bark is this boiling system, which not only cleans the wood but breaks down some of the cork compounds to flatten the bark. The ever more sophisticated fight against TCA continues by using steel rather than wooden pallets. Meanwhile this modern, more aerated boiling machine helps the bark to dry more quickly after treatment, thereby diminishing the risk of mould developing.

No, not a lucrative sideline in sausage manufacture, but a cork extrusion machine. While some top grade corks are punched from a single piece of bark, many cheaper corks – not to mention those used for Champagne – are fused together from smaller granules during this process.

Among the many human and technical tests carried out during the manufacturing process is this check on Champagne corks to make sure they fit criteria for both impermeability and pressure. A fault is detected in around 1 in 10,000 corks, including this one in the middle of the row.

Yet another hi-tech quality check, this time by a machine which scans the corks’ interior pore structure to assess their density before sorting them accordingly into one of seven different grades.

For peace of mind, you can’t beat a last minute check by experienced human eyes. This woman makes sure the Louis Roederer corks are up to the high standards required. In total Amorim alone produces around half a billion sparkling wine corks each year.

Top quality grade bark will be used to create whole-punched natural corks, which are created manually – and very skillfully – by the highest paid team on Amorim’s factory floor.

While Amorim produces a whole range of corks, priced from 2 cents to €2, these finished whole-punched corks demonstrate the sort of quality your money can buy towards the top end of the price spectrum.