I met with Tim Keller of Vinperfect (
www.vinperfect.com) this morning over coffee.
The material presently used for the linings of screw-caps (the material that actually forms the seal) is metalized PET. He is experimenting with other bio-plastics and materials, all of which will be biodegradable.
Essential, a layer containing a small circle of holes is laminated onto a gas-permeable layer; the more holes in the circle, the greater the rate of permeability. While the default rate of permeability is 5 ppm over 5 years, there will be closures that will allow a winemaker to choose differing rates on either side of the default. Point being, each wine is different.
Tim anticipates that the end-user cost will be about $.25 per closure for small orders when the product is ready for commercial release. Release is anticipated in Australia during next year's time of bottling and in this country shortly thereafter. However, Tim is quick to point out that he will not release until he is satisfied with quality and reliability.
As to leeching; since the materials are biodegradable, no guarantee can be made that long term leeching of the materials will not occur. However, he notes that it would be no more than normal corks would incur and that the materials used are, essential, inert.
By long term, we were using an example of 25 years.
My impression was that Tim believes that every consumer should be able to rely upon the fact that any wine closed with his caps will last 5 years without question. Thereafter, longevity and development are a function of the component parts of the wine. Even so, the closure will not break down after 5 years but rather, will continue to allow oxygen ingress (and probably nitrogen egress) for many years to come.
Tim is the first to acknowledge that long term studies of his linings are non-existent. However, he believes that the science behind the project and the testing done to date are sufficient for him to be confident in making his claims. There is some technical data on the website and and e-mail sign-up list for those who wish periodic updates.
Personally, I plan on keeping up with this project as I believe that cork is not the ideal closure for wines, even those to be aged. However, I feel that current screw-caps are best used on wines that will be drunk within 2-3 years of purchase. And further, that red wines under screw-cap are not for long term aging.
So I see these liners as possibly filling a point somewhere between the two.
Best, Jim