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Cork lets sulfur out?

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Peter May

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Re: Cork lets sulfur out?

by Peter May » Fri Jun 15, 2012 6:15 am

I have certainly read in the past that Champagne can be stored upright, doesn't need cork contact. But then that's true for any wine for at least 5 years.

Every single Champagne house I've visited has emphasised that their Champagne doesn't need any more aging, that all the necessary aging has been doen in the winery and that the wine is ready to drink now. (with which I disagree, always keeping Champagne for at least 6 months and often for years).

The US site of the CIVC has this in its FAQs (I can't see anything similar on the mother site at champagne.fr)

1- What are the golden rules for storing Champagne ?
Two essential conditions:
- low and constant temperature around 10°C (50° F) and a high humidity
- storage away from light, noise and vibration


There are millions of bottles stored in crown caps in the cellars of Champagne but the ones I 've seen are all on their side, lying row upon row on top of each other.
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TomHill

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Yup....

by TomHill » Fri Jun 15, 2012 10:03 am

Brian Gilp wrote:
Mark Lipton wrote:The barrels do breathe and let oxygen in, albeit at a slow rate.


Has this been proven to be true? I know it is generally believed to be true but I do recall reading once a text on wine making where the author disputed this claiming that all the oxygen pick up came during the topping up process and not through the barrel staves.


Yup.....Brian has it right. Back in the early '70's, DickPeterson (then Tchelichev's asst at BV) did the experiment in which he put a vacuum gage
on bungs and found, if the bung had a good seal, that it drew a vacuum in the barrel as the wine evaporated. Dick asserted that any O2 pickup
came from the topping up process, rather than any O2 "breathing" thru the pores in the wood.
So where does the head space develop in the barrel as the wine ages?? Beats heck out of me. I assume there must be some
evaporation outwards from the hydrostatic pressure.
Tom
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Mark Lipton

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Re: Yup....

by Mark Lipton » Fri Jun 15, 2012 10:23 am

TomHill wrote:
Brian Gilp wrote:
Mark Lipton wrote:The barrels do breathe and let oxygen in, albeit at a slow rate.


Has this been proven to be true? I know it is generally believed to be true but I do recall reading once a text on wine making where the author disputed this claiming that all the oxygen pick up came during the topping up process and not through the barrel staves.


Yup.....Brian has it right. Back in the early '70's, DickPeterson (then Tchelichev's asst at BV) did the experiment in which he put a vacuum gage
on bungs and found, if the bung had a good seal, that it drew a vacuum in the barrel as the wine evaporated. Dick asserted that any O2 pickup
came from the topping up process, rather than any O2 "breathing" thru the pores in the wood.
So where does the head space develop in the barrel as the wine ages?? Beats heck out of me. I assume there must be some
evaporation outwards from the hydrostatic pressure.
Tom


But, but, but... Tom, oxygen is a smaller molecule than water in most regards. How is that water can make it out of the barrel but oxygen not find its way in? Makes no physical sense to me.

Mark Lipton
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Re: Cork lets sulfur out?

by Paul Winalski » Fri Jun 15, 2012 10:45 am

Peter May wrote:Every single Champagne house I've visited has emphasised that their Champagne doesn't need any more aging, that all the necessary aging has been doen in the winery and that the wine is ready to drink now. (with which I disagree, always keeping Champagne for at least 6 months and often for years).


Peter, I'm with you--that statement from the Champagne houses is just plain not true. In fact, nearly all NV Champagne is released "green". Even NV Krug improves markedly if kept for a year after purchase. I've seen this shown in blind side-by-side tastings of Champagne from a freshly released lot vs. a bottle cellared for a year.

Regarding oxygen getting into Champagne via the cork--seems highly unlikely to me, given the very high positive pressure of the CO2 in the ullage. Were the cork permeable to gas, the outward flow of CO2 would prevent any inward diffusion of O2.

-Paul W.
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TomHill

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Re: Yup....

by TomHill » Fri Jun 15, 2012 11:41 am

Mark Lipton wrote:But, but, but... Tom, oxygen is a smaller molecule than water in most regards. How is that water can make it out of the barrel but oxygen not find its way in? Makes no physical sense to me.
Mark Lipton


Yup, Mark....like I said...beats heck out of me.

Let's assume you have a spherical cow.....errrrrr....an infinite slab of semi-permeable oak. On one side you have O2 (or air) at one atmosphere
of pressure. On the other side you have water at X atmospheres of pressure (whatever the hydrosrstatic pressure is at the bottom of a 2 foot column
of water (wine). Presumably X >>> 1 atmosphere. Now we have a simple transport problem that any idiot should be able to calculate.
(I'd do the calculation...but I forgot how to use the LL3 scale on my treasured Post slide rule)!!!!! :-)
Does the water at the wine/oak interface vaporize and then is forced thru the slightly permeable 1-D slab??? Does the water at the wine/oak
interface vaporize and leak thru the joints/cracks between the staves?? I'm not at all sure. But I can envision the outflow of water vapor overwhelming
any ingress of O2 thru this slightly porous membrane.
Clearly, there is loss of water/wine from an initially full barrel. What's the mechanism for this loss?? Again...don't know. But as the wine is lost,
I'm assuming the headspace is replaced by volatiles/water vapor from the wine which is (assuming a good bung seal) at a pressure << 1 atmosphere.
I'm sure you've visited wineries to barrel sample. Almost always, when the winemaker pulls the bung, you can hear the sucking sound as air rushes into
the headspace. This is consistent w/ Peterson's work way back when. But I don't recall his paper positing a mechanism for the loss of wine from the barrel.
Tom
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John Treder

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Re: Cork lets sulfur out?

by John Treder » Fri Jun 15, 2012 12:07 pm

One atmosphere equals (roughly) 14.7 pounds per square inch, 30 inches of mercury, 32 feet of water.
For mental figuring purposes, I've long used half a psi per foot of water depth.
I have no better idea than anyone else how the water gets out of the barrel. It must actually pass through the oak, or roughness in the joints between the staves, or between the staves and the heads. But just how that happens -- ????
John
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Mark Lipton

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Re: Yup....

by Mark Lipton » Fri Jun 15, 2012 12:11 pm

TomHill wrote:
Let's assume you have a spherical cow.....errrrrr....an infinite slab of semi-permeable oak. On one side you have O2 (or air) at one atmosphere
of pressure. On the other side you have water at X atmospheres of pressure (whatever the hydrosrstatic pressure is at the bottom of a 2 foot column
of water (wine). Presumably X >>> 1 atmosphere. Now we have a simple transport problem that any idiot should be able to calculate.
(I'd do the calculation...but I forgot how to use the LL3 scale on my treasured Post slide rule)!!!!! :-)
Does the water at the wine/oak interface vaporize and then is forced thru the slightly permeable 1-D slab??? Does the water at the wine/oak
interface vaporize and leak thru the joints/cracks between the staves?? I'm not at all sure. But I can envision the outflow of water vapor overwhelming
any ingress of O2 thru this slightly porous membrane.
Clearly, there is loss of water/wine from an initially full barrel. What's the mechanism for this loss?? Again...don't know. But as the wine is lost,
I'm assuming the headspace is replaced by volatiles/water vapor from the wine which is (assuming a good bung seal) at a pressure << 1 atmosphere.
I'm sure you've visited wineries to barrel sample. Almost always, when the winemaker pulls the bung, you can hear the sucking sound as air rushes into
the headspace. This is consistent w/ Peterson's work way back when. But I don't recall his paper positing a mechanism for the loss of wine from the barrel.
Tom


I don't see the pressure differential being large enough to preclude influx of oxygen. As a fer instance, if we introduce nitrogen gas into our reactions [url]under positive (i.e. > 1 atm) pressure[/url] using Tygon™ tubing, we can detect the presence of oxygen in the reaction even if we use >99.9999% pure nitrogen gas (i.e. evaporated liquid N2). That oxygen gets in through the semi-permeable Tygon (5 mm thick) against the pressure differential. I was shocked when we first observed this, but it's a repeatable result. Anyway, regardless of mechanism, I imagine that the wood of the barrel is saturated with water and that water should permit the dissolution of atmospheric oxygen and diffusion through that semi-permeable membrane of oak.

More to the point, we all know the difference between barrel-aged white wines and SS-aged whites. The latter are more crisp and reductive whereas the former are rounder and more developed. It isn't just a matter of oak tannins, is it? I've always attributed those differences in part of slow oxygenation in barrel.

Mark Lipton
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Brian Gilp

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Re: Cork lets sulfur out?

by Brian Gilp » Fri Jun 15, 2012 12:35 pm

Mark Lipton wrote:More to the point, we all know the difference between barrel-aged white wines and SS-aged whites. The latter are more crisp and reductive whereas the former are rounder and more developed. It isn't just a matter of oak tannins, is it? I've always attributed those differences in part of slow oxygenation in barrel.


I don't think anyone is arguing against the slow oxygenation in barrel. Just the manner in which it happens. It it through the barrel itself or a process of topping up the barrel and if so why?

Something I had not really considered until now. If the barrel really does pull a vacuum and O2 does not enter through the barrel itself, then why the need to top up at all? Topping up I thought was to protect the wine from oxidation and other bad things that happen when O2 is present.
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Paul Winalski

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Re: Cork lets sulfur out?

by Paul Winalski » Fri Jun 15, 2012 1:00 pm

I suspect evaporation occurs two ways: between the staves of the barrel, and through the oak itself. Wood is a semipermeable membrane.

-Paul W.
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Howie Hart

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Re: Cork lets sulfur out?

by Howie Hart » Fri Jun 15, 2012 1:24 pm

Paul Winalski wrote:I suspect evaporation occurs two ways: between the staves of the barrel, and through the oak itself. Wood is a semipermeable membrane.
-Paul W.

Indeed. If you put your hand on a full barrel, it is cooler to the touch than a piece of wood lying around the same environment, due to evaporation. As the level in the barrel drops, a partial vacuum forms inside the barrel, sucking air into the barrel, through the wood. I use a silicone bung to stopper my barrel and when I remove it to top up the barrel, there is a mild "pop", not unlike pulling a cork from a bottle.
Chico - Hey! This Bottle is empty!
Groucho - That's because it's dry Champagne.
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Victorwine

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Re: Cork lets sulfur out?

by Victorwine » Fri Jun 15, 2012 5:04 pm

Some might find the following link interesting:

http://www.extension.iastate.edu/NR/rdo ... eCorks.pdf

Salute
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Ben Rotter

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Re: Cork lets sulfur out?

by Ben Rotter » Sat Jun 16, 2012 9:38 pm

In 1998, Moutounet et al. at the INRA conducted a relatively detailed study on barrel pressure, gas composition of the headspace, and micro-strains of the barrel wood. They concluded that gaseous exchange both out of and into the barrel occurred under the condition of vacuum (i.e. low barrel pressure relative to atmospheric pressure). It's complex though, since the degree of exchanges depend on barrel structure, bung position and type, wood treatment, etc.
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