Corking idea:
Stay home, protect the planet, drink wine
Of all the various ways we are being told to help save the planet I’ve found one I like the most: drink more wine.
Not just any wine, the nice man at the world’s biggest cork producer told us, but wine stopped with a cork.
Portugal produces half the world’s cork, and the majority is grown amid the rolling hills and cork oak forests of our new home, Alentejo.
They support a whole sustainable, biodiverse ecosystem known as montado, and cork oak is Portugal’s national tree, protected since 1209, where cutting one down can land you with a hefty fine.
And it is the carbon sink that keeps on giving, according to António Rios de Amorim – the fourth generation chief executive of the 150 year old Amorim cork empire.
“For every single tonne of cork produced we are talking about 73 tonnes of CO2 that are captured,” he said.
“And no cork tree is cut – only the bark is peeled off – which means the tree never interrupts its carbon capture throughout its very long life of 180 to 200 years.”
So every single cork stopper is carbon negative – drink enough, so the argument goes, and you might be able to offset a return flight to Portugal. Just saying.
In the hot Iberian summers, men with axes roam the countryside climbing trees and carefully cutting just deep enough to peel off the cork bark, but not too much to damage the tree.
Every nine years the sobreiros are ready to be harvested again, which is why visitors driving through the Alentejo see fields of naked-trunked oaks, each daubed with a number to indicate when they will next be ready for a trim.
We’ll be heading off for another Alentejo adventure soon to see how cork is harvested – and to learn how laser technology and artificial intelligence is playing its part – but for now let’s talk about the production process.
We were reliably informed that a day in the Amorim cork factories south of Porto would change the way we look at the simple stopper: the final obstacle between us and a lovely glass of wine.
A much-shared myth I fell for in an earlier version of this post is that corks allow oxygen to pass through them into the bottle.
Being elastic and impermeable they seal the wine in nice and tightly and other than perhaps allowing the oxygen already in the cork to interact with the wine in the first few years, create an airtight seal.
The Greeks and the Romans worked this out millennia ago, but it was the late 1700s when glass bottles became the wine vessel of choice and so began an intimate relationship.
And not only have I taken a closer look at stoppers ever since our visit, but my fascination with all its other uses risks turning me into the cork bore at a dinner party.
“This isn’t just about noticeboards, shoes, underlay and insulation,” I might say on the sixth of seventh cork of the evening.
“Oh no – I bet you didn’t know cork is now being used as the base for artificial sports field turf, shock-absorbers for concrete bridges, in electric cars, aircraft and as heat protection for space rockets,” I might add.
But we’re here to talk about wine corks, and last year Amorim produced 5.8 billion of those.
On a vast factory floor we watched some of the 25 million corks produced every day get punched out of cork planks, compressed out of composites, travel up automatic lifts, drop down into huge crates and get zapped clean in machines worthy of a science fiction movie.
One of Portugal’s most important industries faced an existential crisis twenty years ago from plastic corks, aluminium screw caps and the dreaded cork taint.
“I think that's one of the biggest shocks that we ever faced in our industry,” is how António Amorim describes the Naughties.
But thanks to improving technology, changing attitudes towards sustainability and a lot of investment money, cork is fighting back.
“After a traumatic decade from 2000 to 2009, cork has not stopped gaining market share from alternative closures ever since.”
It’s now hard to remember those days when plastic was the solution, rather than the problem – and it had the added advantage of stopping wines from being “corked.”
That has nothing to do with the cork crumbling of course, but an annoying little chemical called 2,4,6-trichloroanisol, or TCA for short.
To the highly sophisticated human olfactory organ, the tiniest of tiny amounts of TCA can ruin a wine, making it smell musty like wet cardboard.
“If you're opening a bottle of champagne, and you have four or five nanograms (of TCA) in it, you will notice,” said Carlos de Jesus, Amorim Cork’s head of marketing and communication.
“That’s the equivalent of eight drops of water in 800 Olympic sized swimming pools.”
Amorim claims to have removed cork taint once and for all with a combination of prevention, removal and quality control.
I’ll save the explanation of thermal desorption and supercritical fluid technology reactors for another post – without the photos as it’s top secret and heavily patented technology – but it’s fair to say António Amorim is confident.
“Today I think that we can clearly say that TCA is something that is done and dealt with - behind our back,” he said.
In fact his biggest concern is not having enough cork for the increasing demand – last year Portugal’s cork industry grew by 12% and was worth more than €1.1bn.
Persuading people to plant more trees is a big ask – it takes an average of 25 years to harvest the first virgin bark which can’t be used for stoppers.
Neither can the second harvest nine years later, so a cork oaks planted today wouldn’t make proper money for 43 years...and that’s too long for many farmers to wait...even into stereotypically slow Alentejo.
Research and development is now going into micro-irrigation systems to help cork oaks reach maturity in ten years rather than 25 and to plant some areas more intensively.
“I believe that if we are serious in the world about sustainability, we should consume everyday products that clearly can capture CO2,” said António Amorim.
So there we have it: protect the planet, drink wine.
researching the cork oxygen permeability question some years ago I found that cork stoppers are essentially impermeable to atmospheric oxygen. It appears that the 'breathing' of cork is a myth. Oxygen passing by diffusion into the bottle stems from the compressed cork itself. The wine essentially receives an initial jolt of oxygen while the bottle gets corked and that's all it ever gets until you open it.