General query on maturity in half bottles

[djewesbury]

I wonder what you'd think about Warre 00 halves that are also in storage? Not sure how long they should be left. I was told when purchasing that they were 'drinking beautifully now'.

I'll extend that into a more general question: what do you all use as a guideline for maturity in halves, all other things being equal? Half the time - 11.5 years..? Or more, or less, and why?

[AW77]

It's good that you've widened the scope of the question. I personaly would welcome a guideline, too. But I'm afraid that it all depends on individual ports with their individual vintages (like so many things in life, there will probably be no easy answer).

[LGTrotter]

I have never had much luck with half bottles. I say luck because I have tended to buy half bottles on the spur of the moment and at retail. There is a gamble on any half bottle of wine in a shop, I am not sure if they are treated less kindly, hang about for longer or are more susceptible to the thousand natural shocks that flesh is heir to. But it seems to me they age disproportionately quickly, I avoid half bottles of port because of this. It is hard to pin down a time limit on them and I am sure that there will be many examples drawn from experience to refute my guess but I would say not more than 25 years. In other words they are on their way out when standard bottles are getting going.

I also admit that I avoid half bottles because they seem a bit meagre.

[DRT]

If we take 750ml bottle maturity as a baseline I think 375ml bottle maturity almost exactly follows an exponential curve.

[TLW]

In which case, what about the maturity of magnums or double magnums? Would these be twice the maturity of a regular bottle? The magnums I have had of older ports have not drank that much differently than regular bottles (next Christmas, by way of experiment, I will give a try at a 77 Graham magnum versus bottle - although there are certainly some questions as to quality of Graham 1977).

If there is a difference between the maturity of a half and full bottle, what would cause this, and would this not apply to larger formats?

[DRT]

In which case, what about the maturity of magnums or double magnums? Would these be twice the maturity of a regular bottle?

These things do not happen in straight lines and bottle variation blurs the picture, but I have no doubt whatsoever that small bottles age faster than large bottles. I suspect it has something to do with the ratio of oxygen to wine in the bottle, small bottles having a greater proportion of oxygen to wine than larger bottles. The same principle is at work in wooden casks, which is why they are topped-up to avoid the wine oxidising too quickly.

[jdaw1]

I suspect it has something to do with the ratio of oxygen to wine in the bottle, small bottles having a greater proportion of oxygen to wine than larger bottles.

That seems very plausible. But how do you know that the problem isn’t with ill-fitting corks?

The same principle is at work in wooden casks, which is why they are topped-up to avoid the wine oxidising too quickly.

Except, of course, those destined not to be drunk until very old.

[djewesbury]

Did I hear the word 'exponential'?
I wonder if halves mature quicker but then follow a different pattern / curve? I mean, why should the plateau or secondary-tertiary transition follow the same proportion as the initial maturation? We need to do a long trial with small, standard and large formats. This should keep us busy into old age.

[PhilW]

Did I hear the word 'exponential'?

Yes, but you missed that it was preceded by "almost exactly". I almost replied "+1.".

[djewesbury]

Did I hear the word 'exponential'?

Yes, but you missed that it was preceded by "almost exactly". I almost replied "+1.".

+2

[DaveRL]

I remember from somewhere that surfaces act as sites for molecules to interact, generally increasing rates of reaction. Surfaces include glass, cork and suspended/deposited particles. Smaller bottles have a higher ratio of glass to liquid. Perhaps this is also a factor?

[djewesbury]

This makes sense; in which case there's no reason why a half bottle would mature twice as fast as a standard bottle. In fact the acceleration could be much quicker; can anyone here work out the internal surface area of the normal half and standard bottles and this calculate the ratio of the liquid to the glass? Thanks.

[JWEW]

If we can approximate the surface area of the liquid to that of a cylinder (which we can only do if the bottle is stored upright) then the surface area calculation is:-

Area=2πrh+2π r^2

Where r is the radius (to internal wall) of the cylinder and h is the height (of the liquid).

[djewesbury]

If we can approximate the surface area of the liquid to that of a cylinder (which we can only do if the bottle is stored upright) then the surface area calculation is:-

Area=2πrh+2π r^2

Where r is the radius (to internal wall) of the cylinder and h is the height (of the liquid).

Yes, go on… Do you need me to measure a bottle??

[JWEW]

If we can approximate the surface area of the liquid to that of a cylinder (which we can only do if the bottle is stored upright) then the surface area calculation is:-

Area=2πrh+2π r^2

Where r is the radius (to internal wall) of the cylinder and h is the height (of the liquid).

Yes, go on… Do you need me to measure a bottle??

If you wish. I have no bottles of any format handy to measure, nor a tape measure to use.

[djewesbury]

Measurements (appx) of the internal, cylindrical part of the bottle:

standard: 65 x 195 mm
half: 55 x 145 mm

internal area of standard bottle = 46456 mm²
internal area of half bottle = 17279 mm²

is that right?
now what?

[JWEW]

Measurements (appx) of the internal, cylindrical part of the bottle:

standard: 65 x 195 mm
half: 55 x 145 mm

internal area of standard bottle = 46456 mm²
internal area of half bottle = 17279 mm²

is that right?
now what?

Don't think that's correct.
For a radius of 65mm and height 195mm I get area= 106185 mm^2
and for radius of 55mm, height 145mm I get an area of 69115mm^2

The volume of the cylinder is πr2h so the volume of the above cylinders will be
2588280 mm^3 and 1377981mm^3

So the surface are to volume ratio for the larger bottle would be 106185/2588280 = 0.041025
and for the smaller is 69115/1377981 = 0.050157

meaning that the smaller bottle has 122% [(0.050157/ 0.041025) *100] higher SA/V ratio than the larger bottle.

I hereby issue a disclaimer absolving myself of all blame in case the above calculation turns our to be rubbish.

[djewesbury]

That seems a very small difference. Is that really sufficient to speed up the development so markedly? Do smaller volumes of liquid do something else differently, in comparison to larger ones?

[DaveRL]

I suspect it has something to do with the ratio of oxygen to wine in the bottle, small bottles having a greater proportion of oxygen to wine than larger bottles. The same principle is at work in wooden casks, which is why they are topped-up to avoid the wine oxidising too quickly.

Am thinking surfaces only a factor. I agree that oxygen concentrations could be the major influence. Suspect it is complicated. If surfaces play a part, then quantity and type of crust and suspended material is also a factor as these would also be sites for reactions.

[Glenn E.]

I suspect it has something to do with the ratio of oxygen to wine in the bottle, small bottles having a greater proportion of oxygen to wine than larger bottles. The same principle is at work in wooden casks, which is why they are topped-up to avoid the wine oxidising too quickly.

Am thinking surfaces only a factor. I agree that oxygen concentrations could be the major influence. Suspect it is complicated. If surfaces play a part, then quantity and type of crust and suspended material is also a factor as these would also be sites for reactions.

The "cork ratio" should be double, though, and that's where the oxygen comes from. (Halves and 750s use the same corks, but surprise! a 750 contains twice as much liquid as a half.)

Double the oxygen, 120% of the surface area, who knows what other factors... there are plenty of potential factors that could explain it. I, personally, would not have said that a 375 ages twice as fast as a 750. That just hasn't been my experience. But they definitely age faster.

[differentdave]

http://www.winespectator.com/blogs/show/id/49398
James laube from winespectator approaches this topic by tasting 18 year old wines from same producer from 5 different bottle sizes (Chateau St. Jean Cinq Cépages 1995 in five iterations: methuselah, jeroboam, magnum, standard and half-bottle.).

[flash_uk]

I remember from somewhere that surfaces act as sites for molecules to interact, generally increasing rates of reaction. Surfaces include glass, cork and suspended/deposited particles. Smaller bottles have a higher ratio of glass to liquid. Perhaps this is also a factor?

This makes sense; in which case there's no reason why a half bottle would mature twice as fast as a standard bottle. In fact the acceleration could be much quicker; can anyone here work out the internal surface area of the normal half and standard bottles and this calculate the ratio of the liquid to the glass? Thanks.

Not sure any of that is relevant, or the subsequent calculations. While it is true to say that surfaces can act as sites for molecules to interact, that is only true if the molecules are of the type that do interact, I think. I'm fairly certain that port and glass do not cause any type of reaction.

I would think that amount of sediment plays a part in maturation, but that is likely to have significant variation between individual bottles and across shippers, which on average would not explain a generally observed trend that 375s mature more quickly than 750s.

Is there really any dispute that the mix of port to oxygen is the most likely and most significant driver of maturation level differences between 375s and 750s?

[flash_uk]

I say all the above, having not actually ever owned or opened a 375 of port. So I have never really examined the fill level on an 375 and what that means for the ratio of oxygen to port in that size of bottle. Is the volume not occupied by liquid in a 375 usually a good bit more than 50% of that in a 750 bottle? If not, then the oxygen/port ratio theory for maturation might be nonsense.

edit:

hence I now also understand Julian's query:

I suspect it has something to do with the ratio of oxygen to wine in the bottle, small bottles having a greater proportion of oxygen to wine than larger bottles.

That seems very plausible. But how do you know that the problem isn’t with ill-fitting corks?

If the cork in a 375 neck is shorter, then could this result in greater leakage of some air into the bottle at a faster rate than with a 750? Or does this not happen? Lots of questions!

[PopulusTremula]

Why can't certain things be allowed to remain mysteries like how does the graphite get crammed into pencils or how are bucatini made?

It seems to me that even a perfect formula for half bottle maturation is still a less satisfactory method than that of pulling a cork on periodic sample bottles.

[DaveRL]

Not sure any of that is relevant, or the subsequent calculations. While it is true to say that surfaces can act as sites for molecules to interact, that is only true if the molecules are of the type that do interact, I think. I'm fairly certain that port and glass do not cause any type of reaction.

I'm fairly certain glass (SiO2 etc) will have some weak ionic forces attracting some molecules in port encouraging mechanical catalysis of at least some reactions. Do decanters not stain red? It doesn't need to be a strong bond, or even for long, to decrease a degree of freedom and speed up a complicated reaction.

Is there really any dispute that the mix of port to oxygen is the most likely and most significant driver of maturation level differences between 375s and 750s?

That was my question - is it an increase in oxygen concentrations, or an increase in the rates of reaction? Worth a thought.