(Reuters) - For three generations Antonio Gorgot's family have carried axes into the mountainous forests of northern Spain to cut slabs of bark off their cork oaks. A few years ago their livelihood was under threat as the cork business lost its buoyancy.
Sales of Spanish cork plummeted between 2008 and 2010 as plastic wine stoppers or metal screw tops made headway globally alongside declining wine consumption.
But now the traditional cork business has recovered, rescued by unlikely saviors: cutting-edge laboratory researchers in white coats who are demonstrating why nature's stopper may still be one of the best ways of preserving and serving bottled wine.
"We're totally in debt to the labs. It's great for our market that they have shown that cork has advantages over other competitors," said Gorgot, 53.
Now natural wine cork production is back at levels of its best times, a bright spot in a Spanish economy that is mired in its second recession in just three years.
Cork cutters and wine producers say the turnaround is largely due to scientists helping them boost the quality of cork production by introducing a strict new European protocol to certify quality corks.
Spain's cork-producing regions of Catalonia, Andalucia and Extremadura have set scientists the task of ensuring corks don't have any infamous "cork taint" - a musty odor caused by the chemical trichloroanisole (TCA).
The Catalan Cork Institute (ICC) in Girona, the largest research institute of its kind, has had its public funding cut but continues its work due to contracts with cork producers and wine bottlers wanting improved standards to give them an edge.
The laboratory tests wine corks and bottles of wine from producers to see which stoppers perform best. It tests whether corks emit smells or contaminating molecules, does a microbiological analysis and also checks out torque and extraction to see how strong the cork is.
Results, which include comparisons with plastic stoppers, are used by bottlers to make buying decisions.
The result is higher quality corks being used for wine, driving out poor quality offerings.
The testing has also shown that sometimes wine tasters have wrongly blamed corks. Juan Pablo Orio, director of research and development at winemaker Bodegas Riojanas remembers: "At a wine tasting in England a client complained that a wine tasted of cork but when we checked on it, it had a plastic stopper."
That kind of scapegoating is becoming less common thanks to cork producers implementing stricter protocols.
The research has also helped cork producers to better market themselves, particularly targeting the more lucrative export market beyond crisis-rattled Spain.
Spain has exported cork since the 19th century and is now the second largest cork exporter in the world, last year selling 300 million euros ($384.03 million) of cork abroad. Spain each year sells 3 billion corks, making 1.3 billion for sparkling wines and 1.7 billion for ordinary wines.
While many mid- to low-range wines are increasingly bottled with plastic or metal corks in big wine drinking countries like Britain and Germany, Spain's producers are now pushing the advantages of traditional cork.
"With the alternative corks people lost sight of the fact that real cork works very well," said Manel Pretel, director of the ICC. "(Synthetic corks) generated problems such as the loss or gain of oxygen which weren't issues with real cork."
Cork can be compressed on bottling lines and then instantly revert to 85 percent of its original size to form an airtight seal for the bottle.
Rival synthetic cork producers have noticed the improvement in natural corks but say there are still many poor quality corks on the market.
The most expensive natural corks are cut from a slab of bark in one piece, but "agglomerated" corks are made from the offcuts glued together.
"Those corks have a chemical that's a lot more aggressive and complex than the plastic we use," said Carlos Valero, manager of ExcellentCork, a synthetic maker in Alicante.
Spain's cork industry says, however, that developments from laboratories like the ICC have led to an improved quality in agglomerated corks.
Increasingly, environmentally aware consumers are also drawn to the fact that growing cork trees helps the planet since forests of cork-oak trees, Quercus suber, remove carbon dioxide from the atmosphere. Also, cork is a renewable resource, since the bark of the tree grows back.
"It's (the) green economy: respecting natural regeneration cycles and respecting the ecosystem," said the ICC's Pretel.
Gorgot and his crew of between four and seven men harvest the cork in the thick forest of Alt Emporda, bordering France, between May and August, searching for the trees planted in higgledy-piggledy formations, rather than rows. An experienced cork cutter can earn 100 euros a day during the harvest season.
A cork tree must grow 25 years for the first harvest, and then it's another eight to 14 years until the next bark has been formed. And the bark is not good enough for corks until the third harvest.
"You don't learn to cut cork in one or two years," said Gorgot. "You need a lot of skill with the axe. You need to leave behind the lower layer of bark that regenerates the next harvest of cork."
($1 = 0.7812 euros)
(Writing by Sarah Morris; Editing by Fiona Ortiz)