WineLovers Discussion Group

Hi. What's your take on the glass vino-seal closure? JC, in another thread, mentioned a glass closure. In the past, the equipment has not been extant for automatic application of such closures. Now it is available, but I am not certain that a headspace purger or vacuum system exists for such a closure. I am worried, of course about oxygen pickup during bottling. Otherwise it seems to make a great deal of sense for higher end wines. Anyone have experience with aging such wines?

I love the vino-seal closure. I have had them from Whitehall Lane in Napa, Syncline in Wash. and some Gruners from Austria. The oldest I've had was a 2005 Whitehall Lane Res. Cab, recently which is not that old but I suspect that they age/mature at a glacial rate if at all.

I like them too. I've mainly experiences from some German producers. Kerpen was a recent one, and there's a Pfaltz producer - Basserman Jordan? - that I've tried too. Oh, an Austrian producer, Praeger I think, as well. I don't worry about oxygen in the neck, as I imagine there is little if any oxygen getting in through the glass and plastic seal. I am curious as to to the differences in O2 stats between cork, screwcap and glass, though.

John S, I'm not worried at this time about O2 permeability, but rather the ability to reduce O2 in the headspace at the time of sealing the bottle. When a cork is pressed in, it compresses the atmosphere in the headspace, and that atmosphere has no choice but to dissolve in the wine. If it has O2 in its composition, that is highly soluble and reactive in wine. If it is just nitrogen, it simply pressurizes the bottle's headspace due to its low solubility, and could contribute to leakage. Standard practice to avoid such possible problems is to inject some nitrogen immediately before corking, then pull a vacuum on the headspace as the cork is going in, hopefully creating a headspace that is little different in terms of pressure from the outside atmosphere (neither promoting leakage in the case of high headspace pressure, or sucking air back through the cork in the case of negative differential pressure. I am unaware whether the automatic vino-seal applicator has any sort of vacuum during the application (not to mention nitrogen or argon injector), but the Otto Sick unit doesn't look as if it has such facility, so I wondered about O2 pickup during closure application. If there is no method of mitigating positive pressure or O2 pickup, but it proves not to be a problem, might as well just apply the Vino-seals by hand.

I have a prejudice in favour of these closures because they are so much more pleasing aesthetically than screwcaps and therefore more likely to be acceptable to European consumers. However I have discussed them with oenologists who point out that their weakness lies in the sealing gasket and additionally there are posts on the Berserker site claiming that there is a high rate of leakage.

Is the rate of leakage higher than the rate of TCA found in the use of standard corks?

James Roscoe wrote:Is the rate of leakage higher than the rate of TCA found in the use of standard corks?

One of the Berserker contributors from the Sierra foothills, whose post reads as if he is a wine grower/maker, claims 2-3 bottles per case leakage rate. He's gone back to screwcaps. Just a sample of one but not contradicted by other contributors.

The TCA rate depends on personal sensitivity but a consensus seems to be traditionally around 5%, which some claim to be in decline as a result of better quality corks.

That seems like a really high leakage rate, but it is only anecdotal. I wonder if their is any hard evidence as to whether the leakage rate is that high for vino-seal. I would guess it is lower than 3-4 per case, but even 1 per case would be worse than 5% of TCA risk.

Thus my question about applicator vaccum to decrease headspace pressure or decrease headspace O2. But the fact is that the only way one would know of leaking bottles is if they are stored upside down or on their sides, and that should be unnecessary with those closures, as there is nothing to keep wet. Stored upright, there would be no evidence of leakage.

As a practical matter, most bottles of wine are going to end up on their sides during the distribution process at some point before final sale. Again, most people store their wine on its side prior to consumption, so evidence of leakage would become obvious at some point between closure of the bottle and actual consumption. I just wonder if there are hard numbers or only anecdotal numbers? I believe the 5% number for TCA taint is pretty well accepted. I know the cork industry claims it to be less and some anecdotal evidence supports numbers around 2%-3%. I don't know of any independent research to support this lower percentage, which I think is still unacceptable.