Reductive characteristics under screw cap - longevity

[malliemcg]

Greetings,

I realise that this one is a bit of an old chestnut but I've been doing some reading and as a result now have questions. It seems that there may be some indicators that the saran-tin screwcaps with really low oxygen permeation rates may have a higher chance to become reductive in the bottle, whereas a different screw cap internal capper may allow more oxygen through, or a cork will not show the mercaptans (compounds responsible for bottle formed reductiveness as opposed to winemaking fault reductiveness).

However it has got me to wondering, if the higher oxygen permeability enclosures do not have these mercaptans than the extremly low permeability enclosure (saran-tin screwcaps), does this mean that the mercaptans formed in the low oxygen environment will go away with a longer period of time as the enclosure eventually lets that oxygen in, or is it a case that they formed at a point in the wine's bottle development and they're going to be around in the wine.

Forgive the potentially controvertial question, but to my somewhat simplistic view of the problem you've got
enclosure X -> lets oxygen amount y in - few reductive compounds formed after time period z - nice wine.
enclosure m -> lets far less oxygen amount n in - reductive compounds formed after time period z - not nice wine described as reductive.
but does
enclosure m -> lets farless oxygen amount n in - few reductive compounds formed after time period (z + t )- nice wine.

Or are there other gotchas due to the massive number of compounds all reacting away in the bottle as it ages and that you'd end up somewhere else completely development wise.

Hoping that some people with more reading and or experience may be able to spread some enlightenment - i genuinely want to know.

[daz]

It's my belief that all wine seals are meant to be anaerobic so I just don't get why corks that are meant to exclude air are so frequently considered to allow its ingress - unless they're dodgy corks. Sure, there were quite a few reports of reductiveness in screwcapped wines when they were becoming more widely used but it's my understanding that wineries have made appropriate adjustments to the use/level of sulphur-based preservatives on the bottling line. And reductive characters also appear in cork-sealed wines.

Yep, hoary old chestnut indeed.

[Sean]

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[Polymer]

Screwcap does not create a total seal against air ingress from my understanding....I think this is actually a proven fact from all the testing I've seen...

I think any winemaker nowadays that thinks some ingress oxygen does not help the wine age is really out of date...I haven't heard that from anyone recently....It might be true but everything I've read suggests some minimal oxygen is beneficial...Too much is bad but a little bit is good...We do know wine ages fine with an imperfect seal (cork) and we have this as factual evidence.

I actually thought the direction of screwcaps was to simulate the oxygen ingress of the best corks...Thus giving you all of the benefits of screwcap and cork...

[dingozegan]

All closures allow some oxygen in, including all screwcap and cork closures. The ingress rate for high quality corks tends to be similar to that for tin lined (IIRC) screwcaps. Whether or not (certain) wines benefit from oxygen exposure (even if at very low ingress rates) while in bottle is still debatable, since (at least to my knowledge) trials have not been conducted on very low ingress vs. zero ingress (and that's possibly because zero ingress is just not a realistic scenario for actual wine bottle closures). Certainly, different liners permit different degrees of oxygen ingress.

These days, the consensus opinion regarding reductive issues in wines with screwcap closures seems to be that the wines that were experiencing such problems were going into bottle in a state too reductive for screwcap oxygen ingress (i.e., many producers were accustomed to using corks that allowed higher rates of oxygen ingress - and their wines therefore didn't show reductive issues in bottle because they had enough oxygen coming in to oxidise the wine enough - but that, with the switch to screwcap, the oxygen ingress was reduced and they therefore had to adjust their winemaking practises to suit). In essence, the opinion is that the screwcap closures just exacerbated existing (minor) reductive problems with those wines that might not otherwise have shown up if using cork closures (that allowed more oxygen ingress).

[dingozegan]

Screwcap does not create a total seal against air ingress from my understanding... I think any winemaker nowadays that thinks some ingress oxygen does not help the wine age is really out of date... I actually thought the direction of screwcaps was to simulate the oxygen ingress of the best corks

Exactly.

[Sean]

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[Polymer]

Screwcaps do allow in oxygen though...They are just far more consistent at how much..

As far as if wine will age completely void of any oxygen...It might...That might be the true best way to age a wine...I don't think there is enough real data to make that determination.

But what we do know..from experience...is with a little ingress of oxygen, wine will age..and many have aged for decades and decades....And they will age the way we want them to...

So let's make the assumption wine will age w/o oxygen...how long will it take to age properly? More time probably? It doesn't appear like less time...Does that mean some bottles will take 100 years to age properly? Do we know it'll actually age properly? We know it'll age but not exactly how...

I'm sure, at some point, they'll have a better idea of what would be the effect of zero ingress...but for now, why would you risk it? We know cork works when the cork is good..why not have that same good cork oxygen ingress and w/o the cork drawbacks? Seems like the best way to go regardless of where you stand w/ cork or screwcap...at least as far as aging goes...

[malliemcg]

Has anyone had any experience with a screwcapped wine that showed (some) reductive characteristics that reduced with age?

I've been trying to find more info - especially with regard to multiple enclosure tests, about how the wines develop over time under say cork and stelvin, but there is not much in the way of definitive answers. Personally I am sitting on the fence with regard to enclosure type, because it seems the more I read the more confused I get.

Perhaps it's just a time of change - not much had changed in the last 150 odd years and now a lot more research and work is going into the production of wine.

Sean - it was some articles on wineanorak that got this train of thought going, followed up by some googling and not much in the way of answers.

[orpheus]

I would be very surprised if the aim of screw-cap manufacturers was to replicate the rate of oxygen ingress of a cork.

It is likely that changes would still occur in a wine that is perfectly sealed.

My own experience of aged white wine under Stelvin is very positive. It develops very well, more like a magnum of wine.

Some of the very old French and Australian wines, which had become ghosts of great wines, would have been terrific to taste under Stelvin.

[daz]

From a James Halliday article on his website:

"There are those – and I am one – who in the future will never buy White Burgundy with a cork closure. Nor will I buy any Australian white wine under cork. And the list goes on from here."

He sat on the fence for a bit when the use of screwcaps was increasing but obviously soon became convinced of the superiority of screwcap seals.

And here's the link to an interesting discourse on reductive characters in wine from TORB's, Ric Einstein's (hope your health continues to improve Ric) site:

http://www.torbwine.com/pa/2006/damnedorscrewed.shtml

[Polymer]

I would be very surprised if the aim of screw-cap manufacturers was to replicate the rate of oxygen ingress of a cork.

It is likely that changes would still occur in a wine that is perfectly sealed.

My own experience of aged white wine under Stelvin is very positive. It develops very well, more like a magnum of wine.

Some of the very old French and Australian wines, which had become ghosts of great wines, would have been terrific to taste under Stelvin.

Why would that be a surprise? No one really knows the long term aging prospects under screwcap. We also know screwcap is not zero ingress..none of the tests have shown that..Maybe the statement shouldn't be replicate..because it already does replicate that of the best corks...it's not zero ingress..

Here's an article I thought was really interesting:
http://www.henschke.com.au/news/?id=12

And while it says it feels the oxygen is negligible. I don't know....There is some..per day..how much of a difference does that make? do we really know? Seems like a lot of arguments on each side....

I'm sure every winemaker wants to rid themselves of cork taint issues...They want to minimize bottle variation..they want to eliminate oxidation issues...and I'm sure there are many places that use cork today, that have bottled some wine under screwcap (as well as others) in an attempt to see the long term prospects of screwcap. I'm sure they've even done things slightly differently to see if there is something they need to do when bottling with screwcap to maintain the level of aging they want.

I'm actually a screwcap fan..I think it'll prove to be perfectly fine...

But that said, everything I have for real aging is all cork...not necessarily by my choice..but that's how they all are...

[orpheus]

Fair enough, Polymer. A number of my long-term cellaring prospects are also cork. Wendouree, Craggy Range Le Sol, Bilancia La Collina, etc.

Others are not.

And you are right, perhaps, that the very best corks are quite similar to Stelvin.

You are also right that I can't tell you whether a wine would age with zero ingress of oxygen. So you are right on all fronts.

You are also right that screwcaps will probably prove to be perfectly fine .

[malliemcg]

Polymer - thanks for that link - something a little more recent than what I'd found before.

Looks like nothing much to worry about, but rather things to be happy about. Just need to have some patience and enjoy the wines (regardless of closure).