Much has been written about the process of wine ageing, mostly about the reaction between air and the liquid. One interesting conclusion is that screw capped (SC) bottle lately shows the propensity of keeping the wine younger, thereby causing some of our collectors lamenting of what vintage should they stop buying in order to enjoy in their later years. Observation of bottles either corked sealed (CS) or SC reveals some interesting facts:
(1) the contact with air really only comes from the ullage, the porosity of the cork material playing only a minute role. My Bordeaux bottles seem to have a very small ullage, usually less than 10 mm thick (to find this, lift up the skirt!). Same as my Yarra Yering Dry Red No 1!
(2) CS bottles are stored horizontally (to prevent the cork to dry up, thereby prevent air to enter!). This shows an elongated air bubble which has a surface contact area (CA) up to 1.5 to 2 Times the CA of the bottle neck. Since most wine storage system is horizontal we shall use this as the standard for ageing time (AT).So we can accept that AT is inversely proportional to CA (that is the larger the CA, the shorter the AT) since contact with air facilitates the ageing process.
(3) if the bottle is stored at 15 or 16 degrees to the horizontal, the air bubble will be at the shoulder, therefore much larger, up to 3 times the bottle neck. Storing bottles this way ensures that the AT will be at least twice the standard AT. Theoretically, my wine would take 2.5 y to age instead of 5.
(4) Riesling bottles have shallow punt and if stored upside down present a CA about at least 4 times the bottle neck!
I have redesigned my cellar for the changes since February, so it is still too early to report. However I just opened two whites for taste:
(1) the 2008 Brokenwood Semillon. This one was 'rescued' from a winestore in 2013 and stored horizontally at home. This is obviously standing all that time in the store so by my calculation, its AT is about 6+. Well, the colour is light gold, the nose is full of lemon, lemongrass and lemon flower. The taste is lemony, with some honey sweetness. So the wine is basically starting on its journey. Luckily I have two bottles left.
(2) the 2009 Alkoomi BL Riesling. This was found in february in a winetore stored standing. I did start storing this horizontally then changed to upside down storing. The estimated AT is then 4.5 y or less. Well, the colour is greenish gold, the nose is lemon, lime. The palate is very long, with flavour of lemon, lime, lime peal and some minerals. Again it shows the wine is starting on its journey. With its lengthy palate, I am not unhappy that I still have two bottles left, as well as the 2013.
So hope this helps your wine ageing.
Dac.
Ageing your own wine
Re: Ageing your own wine
Nice made up science there Dang. I like your enthusiasm!
I suspect the main flaw in your reasoning is that for an unopened bottle with a so-called perfect cork, a slightly increased CA (from a diff storage angle) might only result in a very slightly decreased AT, not some kind of inversely proportional double to halving ratio thing. So doubling the CA might reduce the AT by 2% perhaps? All speculation but hey, why not.
Not so sure that point No.1 is true either, I think the cork or SC has the primary role to play in air ingress, not ullage, although ullage is no doubt a small factor.
I suspect the main flaw in your reasoning is that for an unopened bottle with a so-called perfect cork, a slightly increased CA (from a diff storage angle) might only result in a very slightly decreased AT, not some kind of inversely proportional double to halving ratio thing. So doubling the CA might reduce the AT by 2% perhaps? All speculation but hey, why not.
Not so sure that point No.1 is true either, I think the cork or SC has the primary role to play in air ingress, not ullage, although ullage is no doubt a small factor.
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dingozegan
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Re: Ageing your own wine
Appeciate the thread, Dang, but I'm afraid your first point is incorrect.
There's plenty of scientific research on the oxygen transmission rates (OTR) of corks and screwcaps. These closures allow air to enter the bottle! Corks have OTR around 0.5 uL/day to 20 uL/day (depends on quality and type) and screwcaps have OTR between 0.05 uL/day and 0.5 uL/day (for ROTE with saran/tin liner, Saranex liners have even lower OTR).
Bottle orientation (horizontal vs vertical storage) is potentially significant for wines closed with cork because corks can shrink if they dry out (which they can when in a vertical position), reducing their seal and allowing more air to enter the bottle. For screwcaps, the orientation is irrelvant - their OTR is controlled by the liner, not the bottle orientation or the wine/ullage contact with the liner (from what I've seen, not as much research has looked at this, but there's enough to give an indication).
Ullage (at bottling) can be important, because it can introduce oxygen as you say, but you can't tell whether oxygen has been introduced at bottling just by looking at the ullage because it depends on the bottling method. If a wine has been bottled under vacuum/nitrogen/argon then there wasn't any oxygen in the headspace in the first place anyway!
There's plenty of actual scientific research available on this stuff - just search the web. For example, for more on OTR and orientation, see Lopes et al (2007), Main Routes of Oxygen Ingress through Different Closures into Wine Bottles. J. Agric. Food Chem., 2007, 55 (13), pp 5167–5170 and Skoiuroumounis et al (2005), The impact of closure type and storage conditions on the composition, colour and flavour properties of a Riesling and a wooded Chardonnay wine during five years' storage, Australian Journal of Grape and Wine Research 11:3, 369-377).
There's plenty of scientific research on the oxygen transmission rates (OTR) of corks and screwcaps. These closures allow air to enter the bottle! Corks have OTR around 0.5 uL/day to 20 uL/day (depends on quality and type) and screwcaps have OTR between 0.05 uL/day and 0.5 uL/day (for ROTE with saran/tin liner, Saranex liners have even lower OTR).
Bottle orientation (horizontal vs vertical storage) is potentially significant for wines closed with cork because corks can shrink if they dry out (which they can when in a vertical position), reducing their seal and allowing more air to enter the bottle. For screwcaps, the orientation is irrelvant - their OTR is controlled by the liner, not the bottle orientation or the wine/ullage contact with the liner (from what I've seen, not as much research has looked at this, but there's enough to give an indication).
Ullage (at bottling) can be important, because it can introduce oxygen as you say, but you can't tell whether oxygen has been introduced at bottling just by looking at the ullage because it depends on the bottling method. If a wine has been bottled under vacuum/nitrogen/argon then there wasn't any oxygen in the headspace in the first place anyway!
There's plenty of actual scientific research available on this stuff - just search the web. For example, for more on OTR and orientation, see Lopes et al (2007), Main Routes of Oxygen Ingress through Different Closures into Wine Bottles. J. Agric. Food Chem., 2007, 55 (13), pp 5167–5170 and Skoiuroumounis et al (2005), The impact of closure type and storage conditions on the composition, colour and flavour properties of a Riesling and a wooded Chardonnay wine during five years' storage, Australian Journal of Grape and Wine Research 11:3, 369-377).
Re: Ageing your own wine
(3) sounds wrong. The bubble will be exactly the same volume, no matter which way up the bottle is stored.
Re: Ageing your own wine
Thanks guys for the enlightment on the subject. After all that hard work now I will have to try to drink as much as I can before the taste buds give away. Otherwise our son would be recipient of a good collection!
I do know about OTR, but what really bugs me is how it was measured and how it works. For anything to cross a barrier there must exist either a pressure differential or an incentive, perhaps a chemical absorption. In this case of a horizontal bottle, the outside oxygen molecule must cross the foil to reach the cork. Then it will travel through the porous cork to reach the wet end. It might have now the chance to join up with the phenolic group to perform miracle. The minute OTR sure will have a long time to do that. This process will be much longer for SC's OTR being of much lower quantity, especially for a vertical standing bottle.
So for bottle ageing to work, having a good size ullage seems to be the simplest solution, specially if it is of pure oxygen. The surface contact area (not the volume) would allow the oxygen to find its counterparts and do magic much more readily. This would also solve the complaint of bad smell for SC bottle with no air for ullage (vacum bottling).
These are the reasons for the storage setup (improving CA), the calculations for AT are just approximate, but following simple logic. On the other hand, oxygenation to improve flavour might just be a hoax.
Cheers,
Dac.
I do know about OTR, but what really bugs me is how it was measured and how it works. For anything to cross a barrier there must exist either a pressure differential or an incentive, perhaps a chemical absorption. In this case of a horizontal bottle, the outside oxygen molecule must cross the foil to reach the cork. Then it will travel through the porous cork to reach the wet end. It might have now the chance to join up with the phenolic group to perform miracle. The minute OTR sure will have a long time to do that. This process will be much longer for SC's OTR being of much lower quantity, especially for a vertical standing bottle.
So for bottle ageing to work, having a good size ullage seems to be the simplest solution, specially if it is of pure oxygen. The surface contact area (not the volume) would allow the oxygen to find its counterparts and do magic much more readily. This would also solve the complaint of bad smell for SC bottle with no air for ullage (vacum bottling).
These are the reasons for the storage setup (improving CA), the calculations for AT are just approximate, but following simple logic. On the other hand, oxygenation to improve flavour might just be a hoax.
Cheers,
Dac.