How to put a cork in it: not-to-be-missed factory tour

When the sun is over the yardarm, pop the cork on a bottle of your favourite wine or champagne and examine that speckled tan bottle stopper. Chances are it came from Portugal. We learned more on a cork factory tour.

The country supplies 50 percent of the world’s cork, 72 percent of its cork exports are wine stoppers, and it makes 40 million bottle stoppers a day on average, according to APCOR, the Portuguese Cork Association.

However, it’s no get-rich-quick industry. If you planted a cork oak acorn today, you couldn’t harvest the cork for 25 years – 43 years to get the quality needed for wine or champagne bottle stoppers.

“It’s not so fast,” said Andreia, our enthusiastic and informative guide at Novacortiça cork factory just north of the city of Faro in the Algarve region of southern Portugal. “It’s usually a business that stays in the family.”

Novacortiça, founded in 1986 by the grandfather of the brother and sister who own it now, offers a thorough and fascinating tour of the factory and its nearby cork grove. The tour began in a small conference room, with Andreia passing around samples to handle and divulging countless facts and information about the industry, the harvesting process, and the manufacturing process that constantly surprised us.

• In the hot summer months, the outer bark actually detaches from the trunk. That’s when it’s harvested – from May to September – because the bark comes off easily and doesn’t harm the tree (kind of like peeling a loose-skinned tangerine). If the bark is not harvested, it reattaches for the winter.
• Newly harvested tree trunks are light yellow, but then turn a brick-red hue in a few days. Over the next nine years, the trunk slowly returns to its silvery-grey colour as the bark regrows from the inside out.  
• Cork oak trees are protected by law in Portugal. They must be 25 years old and the trunk must be 70 centimetres in diameter before they can be harvested for the first time. After that, they can be harvested only every nine years. Only the trunk and main branches can be harvested. And no cork oaks – dead or alive – can be cut down without permission from the government. In fact, the first laws protecting cork forests were enacted in the year 1209.
• Portugal is the world leader in cork production, supplying 50 percent, followed by Spain at 30 percent. France, Italy, Algeria, Morocco, and Tunisia supply the remaining 20 percent. Cork oaks grow only in the Mediterranean region, since they love the stable climate and dry soil.

“It’s the only tree that doesn’t die when the bark is harvested,” said Andreia.

Virgin cork is quite bumpy and irregular – not good enough for bottle stoppers since the cork must be even. The second harvest (at 34 years) is more regular, but it’s still not thick enough for stoppers. The third harvest (at 43 years) can finally be used for bottle stoppers.

“It’s really good quality from now on,” said Andreia. Cork oaks can live from 200 to 300 years, so could be harvested up to 20 times.

Andreia explained the production process and then led us through the factory.

Cork is a breathable product and champagne stoppers cannot be breathable, she said. Granules are mixed with a food-grade gelatin to form a tube that becomes the unbreathable top part of the stopper. Then two or more cork discs are stuck to the bottom so that only pure cork touches the champagne. Two or more discs are used so that the holes don’t line up. Then, the stopper is polished and compressed to go into the bottle.

“The pressure in the bottle shapes it into a mushroom,” she said.

Novacortica makes only discs and granules, which are sold to others to make the final products, Andreia explained.

For other products, the granules are mixed with glue, formed into blocks, then sliced into whatever thickness is needed. It can be sliced very thinly into “cork skin,” which is then glued onto a background fabric such as leather or wool or nylon, and used by the fashion industry to make clothing, shoes, coats, hats, ties, purses, umbrellas and even upholstery fabric.

Just about every souvenir shop in Portugal sells cork products and we had wondered how they were made.

After the factory tour, we went to Novacortica’s nearby cork oak grove, where we learned more about the harvest and met the oldest tree – about 200 years old.

Harvesters must be quite strong to do their work. They go through three years of training before they’re certified. Harvesters are unionized and paid very well compared with other agricultural workers, even being paid during the off-season to keep them in the business. Despite that, there are never enough harvesters, Andreia said.

Olive and carob trees are interspersed with the cork oaks in the grove, which makes for healthier trees than a monoculture. About 160 species of birds live in the grove through the seasons, eating bugs that might harm the trees. The critically endangered Iberian lynx also lives in cork oak forests.

“Cork is very complex,” she said. “It’s a sustainable, noble material.”