The nanocork has been developed by British company Bacchus Wine Closures, in partnership with Portugal’s Alvaro Coelho & Irmãos, the world’s second largest producer of corks.
Bacchus Wine Closures utilised existing technologies to apply a special coating – the Bacchus Barrier – to each end of a natural cork providing, the company says: improved anti-oxidation consistency of the cork; dramatically reduced cork taint and other “off” flavours attributed to cork; strengthened cork ends, reducing cork dust problems; improved seal between cork and bottle; improved retention of varietal fruit flavours; extended shelf life.
“It’s tried and tested technologies that make it work,” Bacchus managing director David Taylor told Drinks International. “We’re using a derivative of the typical bag-in-box oxygen barrier. It basically has the same components.”
Taylor insisted that the Bacchus Barrier and its bonding could have no effect on the liquid in the bottle, saying: “We spent a long time researching, developing and patenting a reactive hot-melt polyurethane. It’s not a glue, but it does bond.
“Once it’s bonded it’s completely inert and completely irreversible. And as it’s curing – it takes a day – it actually gets stronger in the presence of moisture.”
The technology for Bacchus Barrier is similar to that already used in supermarket meat trays, and the company’s patent covers the use of the bonding and the film, as applied to the end of a cork.
The company that supplies the film measures the failure rate as: “Less than one in 100 million of one of the discs failing from a manufacturing fault,” according to Taylor. The film, he added, is “thermoformable, so it moulds to any irregularities at the end of the cork, and around the curve at the end without any pleats or creases.”
Permeability to oxygen of the resultant nanocork is: “About the same as a high quality cork – about 0.0005cc’s per day.”
In a two-year project run by the Australian Wine Research Institute, nanocork was compared directly with bottles closed using three other closures: a “reference 2” natural cork; a Supremcorq x2 synthetic closure; and a Stelvin screwcap.
After 24 months storage, the Leasingham 2007 Clare Valley Semillon used in the trial was found to produce “a fresh, intense, fruity wine with long persistence on the palate” under nanocork, while: “Reference Two and Reference Synthetic closures produced relatively similar wines to each other, characterised by honey, esters and oxidation characters,” and: “The Reference Screwcap displayed moderate levels of reductive characters, in particular struck flint, and had a lower fruit intensity.”
Bacchus Barrier technology could, said Taylor, be applied to agglomerate corks, thereby “eliminating any glue tastes”. The company has also tested nanocork with spirits, and has “one customer looking at it” and particular interest from China.
With Taylor’s first customer in Portugal ordering 6 million units, he projects the potential for nanocork as “at least 4 billion corks a year” – approaching the current volumes of both synthetics and screwcap combined.