White Wine Closure

[St. Henri]

Hello all,
Just thinking about the whole stelvin cork debate and come up with a theory. It would make sense to seal white wine ie. riesling, semillon, sav. blanc etc.under stelvin due to the fact that these wines contain no anti oxidents and unlike red wines which do because they are left in contact with skins during the wine making process. Which means that any oxygen let in through a cork becuase of the corks ability to "breathe" would ultimately ruin the wine. though this would not be possible under stelvin. Unless of course the there was oxygen prevelant during the sealing process which would render the process a faliure and probbably the wine would be tainted after long term cellaring. BUT as mentioned earlier red wine DOES contain anti-oxidents so CORK wold be a prefered option as this would allow the wine to breathe as it does require some oxygen to mature fully.
What do you think?
Henri

[Murray]

The problem with your theory is that good corks don't breathe, and for the weaker corks that do breathe, it is inconsistent allowing an enormous variation of air ingress to the wine.

This is also leaving aside the Taint issue.

Along with what is written in Tyson's book "Screwed for Good - the case for screwcaps on red wine" it's worth noting Penfolds recent statements as noted in a VC ad:

Its official. Australia's premier red-wine maker, Penfolds, has adopted the screw-cap. The decision follows a highly successful cork-versus-screw-cap trial bottling of 1996 Bin 389 Cabernet-Shiraz".

Says winemaker, Peter Taylor, " As more time goes by, the greater our preference for the screw-capped bottles. Thay are ageing exactly as you would expect a red of this calibre to age. But the retention of sweet fruit flavour is superior to that seen under cork. And where cork sealed bottles vary in quality, the screw-capped bottles show no detectable variation. The whole winemaking team is extremely excited by the long term quality implications of the screw-cap......... Confidence in the screw-cap is almost certain to lead to a wider rollout across the Penfolds red-wine range.".

[Davo]

The problem with your theory is that good corks don't breathe

Really?


LBM’s oenologists were able to demonstrate that during the first few months following bottling, the cork stopper allowed diffusion of a few tenths of a millilitre of air into the bottle for the first few weeks, then a few hundreths during the next four months. However, this was the average rate of air diffusion. They discovered that the rate of diffusion was extremely variable according to the quality of the cork and even between corks with the same quality rating. As their researchers emphasised, while it is known that ‘oxygen maketh the wine’, it is
also known that ‘too much oxygen spoileth the wine’(ACI, 1980). LBM decided that their new closure must provide sufficient oxygen to permit the wine to age in the traditional way, but at the same time eliminate the variability in oxygen diffusion which was characteristic of the cork stopper.

Quoted from "The failure of a wine closure innovation: A strategic Marketing Analysis."
Brian Marks
Wayne Mortensen

[Murray]

I'm aware of that Davo, particularly as I sent you the paper, and it's a different form of breathing being discussed in our guest's point. Your point refers to the oxygen in the wine at, or around, the time of bottling, not under long term development. But rather than looking at 23 year old researchj, let's look at current thinking.

But such a view is increasingly challenged "I have not seen any evidence that an oxidative (oxygen rich) maturation environment is beneficial for ageing." say cult winemaker Chris Ringland, the face behind such Barossa greats as Three Rivers and Rockford.

Dr. T. Chris Somers is regarded among Australia's pre-eminent researchers into wine development. In discussing data from spectal analysis of shiraz wine stored in ampules under nitrogen, Somers observes that "there is smooth continuous change in all aparmeters. In the same trials the presence of oxygen led to erratic sequential measure and eventually to induced turbidity and colour loss".

In 1976 Jena Ribereau-Gayon wrote, "The quantities of oxygen that normally penetrate into the bottles (in good corks) are infinitesimal if not zero".

Michael Kerrigan of Howard Park "I don't have a long history with reds under screwcap, but I suspect that maturity in a wine is co-factored by the oxygen in the wine to start with, not through oxygen moving through the cork."

Dr. Bryce Rankin (on air passage into wine) "This is in fact untrue. The prevailing belief that cork is necessary for proper maturation of wine is not supported by fact. It is this misconception that has delayed the adoption of Stelvins on red wines."

"I guess the wine industry is still suffering a hangover from the days when corks were thought to breathe." suggests John Casy. "I assume that it is now widely accepted that closures for wine bottles must be effective gas barriers."

In a 1997 AWRI trial "in all cases where permeation was observed (through cork), the extent of oxidation cuased by this characteristic was highly variable amongst corks within a given batch"... The report concluded that "these studies identify variations in cork permiability to oxygen as the major cause of random post-bottling oxidation.

(Screwed for goood? by Tyson Stelzer; 2003)

and so on.

[Muscat Mike]

I was quite sure that I read somewhere that white wines also contain anti-oxidants. Am I correct or not?
MM.

[Murray]

I was quite sure that I read somewhere that white wines also contain anti-oxidants. Am I correct or not?
MM.

Not sure Mike,

But if you eat Pasta with Antipasto is it the same as eating nothing at all?

[Dig]

Ascorbic acid is a powerfull antioxidant and is often added to white wines from warmer regions when the fruit is lacking natural acidity. Sulphur dioxide, as well as being a prservative, acts as an antioxident and is almost always in white wines to some degree, especially those fermented or aged in wood.

[Davo]

But rather than looking at 23 year old researchj, let's look at current thinking.

But such a view is increasingly challenged "I have not seen any evidence that an oxidative (oxygen rich) maturation environment is beneficial for ageing." say cult winemaker Chris Ringland, the face behind such Barossa greats as Three Rivers and Rockford.

This is opinion only. Just because he has not seen any evidence does not mean there isn't any.

Dr. T. Chris Somers is regarded among Australia's pre-eminent researchers into wine development. In discussing data from spectal analysis of shiraz wine stored in ampules under nitrogen, Somers observes that "there is smooth continuous change in all aparmeters. In the same trials the presence of oxygen led to erratic sequential measure and eventually to induced turbidity and colour loss".

Interesting, but there is no mention of corks or their permeability.

In 1976 Jena Ribereau-Gayon wrote, "The quantities of oxygen that normally penetrate into the bottles (in good corks) are infinitesimal if not zero".

28 year old opinion

Michael Kerrigan of Howard Park "I don't have a long history with reds under screwcap, but I suspect that maturity in a wine is co-factored by the oxygen in the wine to start with, not through oxygen moving through the cork."

"Suspect" (his word) opinion.

Dr. Bryce Rankin (on air passage into wine) "This is in fact untrue. The prevailing belief that cork is necessary for proper maturation of wine is not supported by fact. It is this misconception that has delayed the adoption of Stelvins on red wines."

No date and no references, ? just opinion, although I respect the source.

"I guess the wine industry is still suffering a hangover from the days when corks were thought to breathe." suggests John Casy. "I assume that it is now widely accepted that closures for wine bottles must be effective gas barriers."

Suggested opinion

In a 1997 AWRI trial "in all cases where permeation was observed (through cork), the extent of oxidation cuased by this characteristic was highly variable amongst corks within a given batch"... The report concluded that "these studies identify variations in cork permiability to oxygen as the major cause of random post-bottling oxidation[/size].[/quote](Screwed for goood? by Tyson Stelzer; 2003)

Hmmm, seems to be the same as the ROTE research I quoted.

And why is published research, no matter how old, not relevent? If the experimental model was sound the findings should still be sound today. This should be especially so when the testing is performed by the very company which you are so avidly supporting and the findings are quoted in an article you are using to support your stance. Just another case of selective quoting to support your case I guess.

[jezza]

Ascorbic acid is a powerfull antioxidant and is often added to white wines from warmer regions when the fruit is lacking natural acidity. Sulphur dioxide, as well as being a prservative, acts as an antioxident and is almost always in white wines to some degree, especially those fermented or aged in wood.

Sorry Dig but a quick point of order, acsorbic acid is rarely if ever used to acid adjust wines, wayway too expensive in comparison to other alternatives like tartaric acid (which is bloody expensive anyway). Ascorbic Acid is used a catalyst to shake off bound Oxygen in the wine so that the Sulphur can scavenge it strait away. Plus you always ensure that there is free sulphur in the wine prior to adding ascorbic as you will oxidise the wine.
From memory so I think I'm right

Cheers

[Murray]

Davo,

Selective? Absolutely, but there was no quote out of context or incomplete. I was selective due to the number of sources at my disposal and the time spent in writing the post.

As I said in my note your point refers to the oxygen in the wine at, or around, the time of bottling, not under long term development, which was the premise put forward in the original post.

There is also insuffiecient detail in the papaer available to both of us on how this was 'shown', and the nature of the diffusion, whether through the cork or in the cork/glass interface.

btw John Casey, he of 'suggested opinion', was the former chief chemist for McWilliams Wines and has authored a number of articles on corks, including those I've seen in the Australian Grapegrower and Winemaker

[Dig]

Sorry Dig but a quick point of order...

Thanks Jezza, happy to be put straight. The original question:

I was quite sure that I read somewhere that white wines also contain anti-oxidants. Am I correct or not?

You'd have to say yes. Yes?

[jezza]

yep thats right

[Davo]

Davo,

Selective? Absolutely, but there was no quote out of context or incomplete. I was selective due to the number of sources at my disposal and the time spent in writing the post.

Murray, you should become a journalist with a major weekend paper.