Cork. It’s more than a detail.

The process of harvesting the cork oak takes precision, years of practice, and a good axe.

In the Alentejo region of Portugal, workers spend their summers delicately removing the outer layers of the trees by hand before sending them to be processed into something more recognizable: cork.

Natural cork has been used in winemaking for centuries and is still the stopper of choice for 89% of Wine Spectator’s top 100 wines.

Portugal has the largest cork oak forest by area in the world.

While it takes around 15 years for a cork oak tree to grow its first layer of cork, it is harvested in cycles of nine years. And only from the third harvesting on — or 27 years later — the raw material called amadia cork is ready for processing.

Cork worker Simão Fortio started harvesting cork when he was 15 years old. At 45, he has been harvesting cork for over 30 years. He explained that he and other workers harvest the cork during the summer with axes. Oftentimes, men work in pairs to help each other, “very carefully not to harm the tree.”

“It’s very difficult. It takes a lot of knowledge to remove the cork without hurting the tree,” Fortio said.

Portugal is the world leader not only in cork extraction, harvesting 100,000 tons of it a year, but also in selling cork products.

“2018 was an historical year for the cork industry,” said João Rui Ferreira, President of the Portuguese Cork Association. For the first time, Portugal exported more than 1 billion euros’ worth of cork, he added.

Wine stoppers make up the majority of the market, representing 70% of total exports.

“Knowing that 40 million cork stoppers are produced daily in Portugal, it’s very likely that when you’re opening a wine bottle, the cork stopper is coming from Portugal,” Ferreira said.

To discover more information about the natural cork harvest, read this article via Business Insider.