The secrets of cork: So much more than a bottle stopper

Lisbon, Portugal – The sound of a cork popping from the end of a bottle is known around the world. It often precedes moments of celebration, a shared meal or simply the quiet enjoyment of a glass of wine. But many who have participated in the simple ritual may not realize that it is also synonymous with sustainability, natural wonder and even human ingenuity.

Cork, the humble material used for centuries to seal bottles, is a unique product not only because of the way it is grown, but also because of the many inventive uses people have found for it, which go far beyond the ubiquitous bottle caps. Cork is used in everything from building spacecraft to insulating homes, and it can replace rubber or plastic in almost anything that needs protection from heat or vibration.

Thanks to the unique and delicate conditions in which it grows, cork is also a powerful natural carbon sink, meaning it absorbs harmful CO2 from the atmosphere and locks it away.

CBS News visited the southern European nation of Portugal, which produces most of the world’s cork, and met António Rios Amorim, who humbly rejects the title “King of Cork.”

“I’m just inheriting a huge legacy from a family that, for the last 154 years, has been dedicated to cork, and really trying to develop this unique product to give it new life,” he said.

Amorim Cork produces more than five billion of the approximately 13 billion cork bottle caps produced annually worldwide. It’s enough to give the family business a comfortable supremacy in the industry, but Amorim said finding new and innovative uses for the material beyond sealing bottles remained “fundamental” to the future of his empire .

Among the lesser-known applications, and one that Amorim clearly appreciates, is the use of cork in NASA rockets. The material mixes with the heat shields that protect spacecraft as they exit and re-enter Earth’s atmosphere.

Its light weight, malleability and vibration-isolating properties have made the spongy material a natural choice for some of the most important space missions, including the Apollo missions and Mars rovers. It is also used in Elon Musk’s SpaceX rockets.

“It’s remarkable,” said Eduardo Soares, as he gave CBS News a tour of Amorim’s eclectic showroom. “Cork has this very peculiar effect, a slow burning process. It will absorb the heat without transferring it.”

As head of the unit tasked with imagining new ways for Amorim to make use of cork that’s not suitable for bottle caps, Soares could easily identify every product in the room.

Biodegradable cork granules replace rubber in artificial turf infill, which also helps keep surface temperatures low and prevents the release of microplastics; Isolation panels that absorb vibrations, making train cars quieter and smoother; Playground floors, usually made of synthetic materials, now have a natural alternative.

For Amorim, the list of alternative uses for cork seems endless.

“For us it is very important that we use the raw material that we take from nature to the last limit”, explained Soares.

Amorim is also part of a recycling initiative, aptly named The Cork Collective, which aims to help restaurants and hotels recycle the corks from the bottles they open, to give the valuable material a new lease of life.

Another family business in the sector is Sofalca, which specializes in turning cork into a natural insulator for walls and floors.

CEO Paulo Estrada gave CBS News a tour of his factory’s autoclaves, affectionately nicknamed the “popcorn makers,” which cook cork granules at high temperatures and under intense pressure. The cork expands and its natural resin sticks it all together without the need to add chemicals. A large block rolls off the assembly line, ready to be carved into slabs, molded into huge wall art or even furniture.

Estrada said the material can give a “contemplative effect” to a modest part of someone’s home.

“If you approach a cork wall, you will touch it, smell it and feel it. Nobody remains indifferent,” he added.

The companies’ desire to make the most of every ounce of natural material can be explained by their biggest caveat: cork is a layer of bark that only grows on the Quercus Suber oak. It usually takes 25 years from the time a tree is planted to be ready for its first harvest. It then takes another nine years for the bark to grow back.

“You have to be patient,” said Casimiro Milheiras, taking a quick break from climbing trees with a small axe. Milheiras, 57, is one of thousands of seasonal workers hired each summer to comb through Portugal’s scorching Alentejo region to hand-cut the bark of Quercus oaks.

“It’s almost an art form, so only do this work if you really enjoy it,” he said.

His 20 years of experience have taught him exactly how to hit the tree hard enough to pierce the bark, but not so hard as to cut the trunk, as doing so would compromise the next harvest.

However, the natural landscape of cork is not only important for the industry. Environmental impact studies by international consultants EY and PricewaterhouseCoopers have shown that many of Amorim’s products are actually carbon. negativemeaning that the overall process, from growing to extraction, transport and production, absorbs more carbon than it emits into the environment.

“There is no better example of a carbon sink in a forest than the cork oak, because we don’t cut the tree,” explains Nuno Oliveira, “we want them to grow. [for] as much as possible.”

Oliveira is the director of Amorim’s forestry division, responsible for the research and practices that keep its cork oak forests healthy. Their work helps secure the future of both Portugal’s cork industry and the company.

Standing in a field of oak trees planted on average 100 years old, Oliveira explained that as long as the trees continue to grow and regrow their precious bark, they will continue to suck carbon from the air.

His biggest challenge, he said, has been finding ways to shorten the time it takes for a tree’s first cork harvest from the current 25 years to just 10, which CEO Amorim highlighted as one of the questions more “fundamentals” that your business needs. to answer

“This is a gift from nature,” Amorim said. “We must consume products with a negative carbon footprint. This means we will have to plant many more cork trees, which in the end will make us live in a much better world.”