Glass Cork, Anyone?
It is difficult to get any decent Spanish wine in the restaurants here in Malta. We ordered a bottle of Sicilian wine the other day with our meal, to my big surprise, it came with a glass cork. There has been a lot of much discussions on screw cap on different blogs and forums on screw cap, for example, hop over to, openwineconsortium.org forum lately, you will see how the topic sparked a lot of interesting and informative discussions from many different points of view on the thread. But glass cork? This was the first time I have seen a glass cork in real life.
After a bit of digging on the Internet, I found that these glass corks are made by CSI Closure Systems International, a manufacturer of screw caps for beverages, a branch of Alcoa Inc., USA. They went into production at the end of 2005. The glass corks are being marketed as Vino-Lok in Europe and Vino-Seal in the US. Apparently there is a slight difference between Vino-Lok and Vino-Seal. According to the Alcoa website. The only difference between the two glass stoppers is that Vino-lok uses an aluminum cover cap, while Vino-Seal(TM) uses a tin capsule over the glass cork.
As far as I could find, it was first blogged by The Wine Rack back in August 2006. Recently, Wino Sapien from Australia also blogged about it. The comment from Anonymous, a wine maker, was very informative. He or she said, “….50 cents per top for Vino-Lok, the same or less than the price of a high quality cork. The price per case of the German made Vino-Lok finish bottles is lower than the price per case of comparable quality cork finish bottles. Stelvin is about 17 cents a piece, but the stelvin finish bottle is the most expensive per case.”
The glass cork has a ring which I thought was silicon. But it was actually some substance called DuPont™ Elvax® eythylene-vinyl acetate. It is supposed to be durable and insoluble in alcohol and resistant to weak acids and other wine constituents.
A glass cork definitely carries a more upscale image than a screw cap. The manufacturer claims that the wine that uses Vino-Lok or Vino-Seal will develop more slowly than in a traditional cork sealed bottle giving it longer aging potential. The Sicilian wine we ordered was too young for us to judge.
Has anyone tasted any wine sealed with a glass cork that has been shelved in a bottle for a few years?
Tags: glass cork, Vino-Lok, Vino-Seal
July 9th, 2008 at 7:56 pm
I first encountered Vino-Lok closures in February 2004, during a visit with Klaus-Peter Keller at Weingut Keller in the Rheinhessen. He was experimenting with them, bottling by hand in small lots, to decide whether he wanted to go with them in the future. He did not (he’s since started using Diam closures for some of his basic wines), but many other German producers have. In fact, Germany seems to be the country that’s implementing the Vino-Lok more widely and rapidly than any other.
That said, I’ve yet to try any Vino-Lok’d wines with any more than about two years of bottle age. They were far from old wines but there were no signs that anything was progressing in an abnormal way.
July 13th, 2008 at 2:44 am
Thanks for the mention.
Interestingly in Australia, some of the top end, who have been reluctant to embrace screwcap (eg Penfolds Grange and Henschke Hill of Grace - Australia’s two most acclaimed wines) have mentioned they are trialling or at least considering glass stoppers.
July 14th, 2008 at 9:27 am
@David, perhaps the fact that these glass corks are made in Germany probably makes marketing them in Germany more effective resulting in more German producers adopting Vino-Lok.
@edward, do you know if these high end wine producers in Australia have not adpoted the screwcaps because they do not carry an upscale image or they have reservations about how their wine will age in a screwcaped bottle?
July 18th, 2008 at 4:31 pm
I like these glass tops so much more than screwcaps.
I’m also curious about the Zork
http://www.zork.com.au/
Just the sound itself is great marketing…
July 21st, 2008 at 7:21 pm
@Dirty, I checked out the zork website. I think if I have to choose between the glass cork, zork, or screw cap, I would choose glass cork. I don’t know if I am imagining but I thought I used to see something similar to zork but with a cork in the middle instead! But no matter how hard I try, I just cannot recall what kind of product it was. Last night we opened a bottle of wine from Australia, screw cap again! Screw caps seem to be very popular among Australia wine. I have seen them on Austalia wines only so far.
July 25th, 2008 at 10:08 am
I think it is a little bit of both. Penfolds and Henschke have embraced the screwcap for whites and also ‘lesser reds’ (eg up to $A50), but still the top end is cork sealed. I can understand some of the reluctance, but in time more data will emerge. Many smaller producers of quality wines ($100 plus) have decided and they use screwcap or DIAM. I have a lot of confidence in both seals, though time will tell if it has been misplaced. . .