How can a wine 'age' under a screwcap?

[Charles Emilio]

G'day All,
My first post on here.

I'm an Aussie who runs an importing business based in Lima, Peru.

Tonight I presented a tasting and one of the wines I presented was Lake Breeze Bernoota 2006.
Everyone who tried it liked it and all agreed that it needed a good 3-5 years in the cellar however they all expressed doubts that it could age because it was under a screwy, and since screw caps dont permit any oxygen to enter the bottle it is not going to age for better or worse.

Therefore I ask the question how does a wine age under screwcap?

cheers to you all

Charles

P.S - I really miss the great variety of wine available in Australia, especially those gorgeous cool climate Shiraz

[Red]

Charles,

I'm sure others will chime in here with more detailed, knowledgeable answers than mine, but wines under screwcap do age. They do let oxygen in, but at a lower, more consistent rate than cork. Which means that your wines under screwcap will in the vast majority of cases age at a consistent rate (which in my opinion is exactly what you want).

[Michael McNally]

There is also a certain amount of oxygen in the wine in the bottle when it is sealed,regardless of what it is sealed with. Even if there were absolutely no ingress of oxygen, the oxygen already in the liquid would "age" the wine. That's my (non-professional) understanding.

Cheers

Michael

[Michael R]

the oxygen already in the liquid would "age" the wine. That's my (non-professional) understanding.

Same for me.

[daz]

I'm with Michael too.

A perfect cork seal allows no ingress of air to the wine in the bottle That's your main argument against oxygen thieves who mistakenly believe a cork should so do. Water is more invasive than air yet there have been reports of old, still drinkable wines recovered from shipwrecks, presumably with perfect corks. I've increasingly seen comments from James Halliday such as "perfect cork", "pity about the cork", "oh for a screwcap" - seriously. If the elder statesman of Australian wine critics has become a firm proponent of screwcap seals for wine, given his extensive experience and no doubt expansive cellar(can't help but wonder if he ended up with some of Len Evans' classics, probably not that he'd need to), I think speaks volumes for the superiority of screwcaps. Just imagine the number of cork sealed wines he's tasted over the years that were TCA'd, oxidized, overly brett'd.

The "Luddites" thread on *Forum ended up with screwcaps having a failure rate lower than that of cork but not as manifestly so as I'd expected. Perhaps the result was slightly skewed by individual preferences/tolerances of brettanomyces, very low level TCA and dislike of reductive characters, the latter reputed to be more often present in screwcapped wines than cork sealed. Reductive characters in screwcapped wines seemsto have become less of an issue as winemakers have adjusted the preservative level to suit screwcapped wines. There's the "just didn't like the wine so I'll ascribe a reason" factor. Reductiveness is a bit of a moot issue. It's generally a result of sulphur-based preservatives that appears in both cork and screwcap sealed wines. It usually dissipates with breathing. Obviously a damaged screwcap can result in oxidation of the wine. TCA can appear in wines under screwcap if it's present in a winery, eg barrels the wine is stored/aged in.

Cheers

daz

[Roscoe]

Charles,

I'm sure others will chime in here with more detailed, knowledgeable answers than mine, but wines under screwcap do age. They do let oxygen in, but at a lower, more consistent rate than cork. Which means that your wines under screwcap will in the vast majority of cases age at a consistent rate (which in my opinion is exactly what you want).

This is also my understanding. I think studies by AWRI show that the rate of transfer of oxygen is low, but measurable and quite consistent under screwcap, and that this rate is similar to the "best" corks, which are not as consistent. How important this transfer is, is a matter of debate.
My personal experience (FWIW) is entirely consistent with this. My older screwcap wines (around 7-8 yrs old) are definitely ageing but at a similar rate to a "very good bottle" under cork and with less bottle variation. So far so good.

[rens]

This is my understanding:
Ultimately wine is a chemical reaction occurring in a bottle-a slow chemical reaction. The chemical reaction is influenced by oxygen and temperature(amongst other things). The warmer it is the faster the reaction goes. When exposed to oxygen the chemical reaction occurs differently when not exposed to oxygen.
Oxygen exposure is severly limited by both a good cork and a screw cap. The less oxygen that enters the chemical reaction the better the end result of the chemical reaction. To much oxygen gives you an oxidised wine.No oxygen exposure gives you a near perfet wine.
This is similar for temperature. The temperature level that is regarded as the best for the chemical reaction that we call wine is about 14 C. Hotter temps increase development in certain chemicals in the wine chemical reaction and thus gives you heat effected wine. Lower temps dramatically slow the reaction and give you an under developed wine.
Ultimately it does not matter what is stopping the oxygen from entering the wine, as long as the wine is not comming in contact with oxygen.
So in short the closure does not effect the wines ability to age. The chemical reaction that ages wine will occur under any seal.

[Broughy]

Not sure you need additional oxygen to age a wine? It is part of the puzzle but not the only part. Seems the arguement is the rate of ageing i.e. you could argue that by allowing additional oxygen into a wine sealed with a cork that you are prematurely ageing the wine and exposing it to oxidisation.

[Capel Vale Wines]

The reason for the change over to screwcaps was due to the discovery that wine develops anaerobically (without air) and therefore the theory of the cork allowing air into the wine was defunct.

Check out the FAQ we have placed up on our web because we bottle exclusively under stelvin:
http://www.capelvale.com/appreciation/screwcaps

Cheers

Scott - Capel Vale Wines

[David]

The reason for the change over to screwcaps was due to the discovery that wine develops anaerobically (without air) and therefore the theory of the cork allowing air into the wine was defunct.

Check out the FAQ we have placed up on our web because we bottle exclusively under stelvin:
http://www.capelvale.com/appreciation/screwcaps

Cheers

Scott - Capel Vale Wines

Hi Scott

You beat me to the punch. I was going to say what you said.

[Charles Emilio]

Thanks for the responses, I thought the same thing, that wine ages naturally because of the oxygen in the bottle and that light, movement and heat are it's natural enemies.

You can't argue with potential clients, so I let them convince me that a wine needs a litle bit of continuos air in order to 'age'

Thanks for the help

cheers

[redstuff]

I prefer to stay well clear of such arguments on the chemistry of wine as it is such an extremely complex beast with a myriad of reactions taking place: from reactions such as the oxidation of ethanol to acetic acid; to oligmerisation and polymerisation reactions of phenols to make anthocyanins etc. I would bet my left testicle that if u excluded all oxygen in the form of molecular oxygen (O2) from the system from the time of bottling, that reactions between molecules would continue - the end result would be something completely different to a system in which oxygen was allowed. Energy through the environment such as heat or visible light can and will promote chemical reactions.

my 2 cents

[griff]

I think redstuff's left testicle is safe. Just remember the screwcap does allow some oxygen. It may not be much but it is enough to age wine. In some wine it can cause a problem if the wine goes into the bottle with too much sulfur as reduction may occur etc. Of course that is a gross oversimplification as I don't understand sulfur chemistry very well at all.

With what rens said its close to what I think but I prefer to think of the situation as multiple chemical reactions occurring at once. They all have different rate constants and different activation energies. At around 12-16 degrees and with minimal oxygen (the screwcap is equivalent to the best cork according to AWRI trials) you have the best conditions for the chemical reaction system for the beneficial ageing of wine.

cheers

Carl

[Capel Vale Wines]

Great minds think alike David

Scott - Capel Vale Wines

[GraemeG]

Great minds think alike David

Scott - Capel Vale Wines

Hi Scott,In view of the variously passionate arguements advanced to and fro on this subject, can you say anything about copper fining?
I'd be led to understand from certain quarters that this is the routine treatment to prevent reduction, and in view of the EU rules, public health standards and so forth, that wineries around the land are all slowly poisoning us as a side-effect of being too embarrassed to admit that screwcaps are no good after all.
Do you copper fine? Did you before? Has the regimen changed since moving from corks to screwcaps?
cheers,
Graeme

[Capel Vale Wines]

Great minds think alike David

Scott - Capel Vale Wines

Hi Scott,In view of the variously passionate arguements advanced to and fro on this subject, can you say anything about copper fining?
I'd be led to understand from certain quarters that this is the routine treatment to prevent reduction, and in view of the EU rules, public health standards and so forth, that wineries around the land are all slowly poisoning us as a side-effect of being too embarrassed to admit that screwcaps are no good after all.
Do you copper fine? Did you before? Has the regimen changed since moving from corks to screwcaps?
cheers,
Graeme

Graeme,

Sorry I have been offline recently hosting some VIP's down at the winery. I'll check with the winemaking team about this and get back to you.

Scott - Capel Vale Wines

[KMP]

If oxygen is needed for the maturation of wine do different wines need different amounts of oxygen (i.e. less for a Pinot than a cabernet)? Some folks think so. Advanced Enological Closures has designed a "breathing screw cap," which has small vent holes and is fitted with a liner made of alternating layers of thin metal and a porous polymer. The liner can be customized to allow optimal oxidation for specific varietals, something that is impossible with bark corks. A patent is pending for the design. High-Tech Wine Cap Design Wins. “We will end the screw-cap debate,” Keller said. “Our product will give a level of control that the wine industry has never had.”

A problem with this approach is that we don’t all keep wines for defined periods – some drink their purchases as soon as they get home from the bottle shop while others may lay the same wine down for years (i.e. some like the primary fruit while other like developed flavors). So would the same liner be appropriate for both camps? I don’t think so, which means that the same wine should have different liners letting in different amounts of air and you pick your bottle based on how much air you think the wine needs. Just imagine how complicated wine shops would become with the same wine having color coded screw caps indicating the amount of air allowed to enter the bottle.

Mike

[daz]

I tend to the opinion that the small quantity of dissolved oxygen in wine when bottled is one of the factors in its maturation, along with other reactions in its complex chemistry. And I'll reaffirm my opinion that the more anaerobic the seal, the better.

daz

[Capel Vale Wines]

Great minds think alike David

Scott - Capel Vale Wines

Hi Scott,In view of the variously passionate arguements advanced to and fro on this subject, can you say anything about copper fining?
I'd be led to understand from certain quarters that this is the routine treatment to prevent reduction, and in view of the EU rules, public health standards and so forth, that wineries around the land are all slowly poisoning us as a side-effect of being too embarrassed to admit that screwcaps are no good after all.
Do you copper fine? Did you before? Has the regimen changed since moving from corks to screwcaps?
cheers,
Graeme

Graeme,

Copper fining is used with corks or stelvins throughout the wine industry and the amount used is well below world health standards. The regimen hasn't changed under stelvin and we seal every wine under Stelvin now.

Scott - Capel Vale Wines