ThePortForum.com

A detail that has nagged me for a while is the possibility that vintage port evolution might not just be a matter of time in the decanter, but might also be associated with the formation of a spiritous surface layer, which, when drawn off, leaves the good wine below.

So a simple experiment.

My victim was a Graham '77; a wine that has some history for needing a long decant. After decanting, I left the decanter stoppered and untouched for 27 hours before drawing a glass.

At the time of decanting, I supped the dregs from the bottle, and found them to be rich, aromatic, and free of taint.

So I was surprised to find the first glass from the decanter (poured carefully to avoid unduly disturbing the contents) to be clearly corked.

I was also annoyed, as I have had more than my fair share of tainted bottles this year.

A second glass was also clearly tainted - Ok to drink, but with a soggy cardboard nose.

Later I drew a nightcap, and found the taint was barely noticeable. Now, at D + 46 I have poured another glass and found it completely free of taint.

For the purpose of the initial experiment, I found the wine to be fully integrated at D + 27, with no excess spirit; so tentatively conclude that it is indeed time alone that causes a decanted bottle to evolve.

BUT.. given a little time, does TCA taint migrate to the surface, whence it may be drawn off?

Could I ask anyone encountering a corked bottle to put the decanter to one side for a day or so, then carefully draw off a glass or two without stirring up the contents of the decanter - and see whether the remaining wine is then freed from taint?

Tom

Why not use a pipette to draw one glass of wine from near the surface, and one from near the base of the decanter?

Why not use a pipette to draw one glass of wine from near the surface, and one from near the base of the decanter?

Whilst I have some pipettes, and will attempt just that when the next opportunity presents, I doubt that many are thus equipped.

Tom

I'll try it when I find my next corked bottle. I'm curious to know the result....

uncle tom wrote:

Why not use a pipette to draw one glass of wine from near the surface, and one from near the base of the decanter?

Whilst I have some pipettes, and will attempt just that when the next opportunity presents, I doubt that many are thus equipped.

Tom

i happen to have two long draw pipettes,

port only or will dry reds worrk in the experiment?

actualyl what's interesting is that TCA (density ~1) is more dense then ethanol (density .789), so the bottom draw should actually contain more tca then the top.

looking at the anisole family .
http://msds.chem.ox.ac.uk/AN/anisole.html

it looks to be tca is neglible solubility in water, so that tca actually doesn't integrate with the liquid component but being of the same density (just slightly less then water) if you wait long enuf, it might actaully be the "middle" layer that contains the tca.

It sounds very plausible that you could be correct tom.

actually as i think about it

if you could do it in a beaker ..
if you know the alcohol by volume content, say 18%

then you could theoritcally draw off the top 18% of the beaker which should leave a bottle of tca,
and everything in between should be the good stuff.

Alcohol and water are extremely miscible. Indeed, they are so miscible that a litre of pure water plus a liter of pure alcohol makes considerably less than two litres of liquid. So if the TCA separates, it is either at the top or at the bottom, as there is definitely not an internal water-alcohol boundary at which it might be concentrated. Top or bottom, not 18% of the way anywhere.

yea, i just had to think more clearly,

alcohol and water are strong attracting molecules.

i found the msds for TCA as oppose to anisole (main component without the tri chloro)

http://www.lookchem.com/cas-503/50375-10-5.html
this is 2,3,6 TCA as oppose the more stable 2,4,6 tca. but density would be the same for the two components.

density is actually 1.416 g/cm3 which would make it heavier then water

I think you'll taste TCA no matter how you siphon the bottle, decanter, or beaker. A little TCA goes a long way if you are sensitive to it.

uncle tom wrote:Whilst I have some pipettes, and will attempt just that when the next opportunity presents, I doubt that many are thus equipped.

I’d be interested in hearing whether there is a notable difference between the top and bottom of a well-decanted decanter of Port. Perhaps the pipette should be inserted at decanting time to avoid contamination?

If this experiment is sucessful, it might cause a revival of those miniature barrel-shaped decanters!

mosesbotbol wrote:I think you'll taste TCA no matter how you siphon the bottle, decanter, or beaker. A little TCA goes a long way if you are sensitive to it.

Without aiming to divert this post, is there any truth in Wikipedia’s cure?

Wikipedia wrote: One method of removing TCA from tainted wine is to soak polyethylene (a plastic used for applications such as milk containers and plastic food wrap) in the infected wine. The non-polar TCA molecule has a high affinity for the polyethylene molecule, thereby removing the taint from the wine. The surface area of polyethylene needed to reduce the taint to sub-threshold levels is based on the TCA level in the affected wine, temperature, and the alcohol level of the wine.

This can be done at home, as advocated by Andrew Waterhouse, professor of wine chemistry at University of California, Davis, by pouring the wine into a bowl with a sheet of plastic wrap. For ease of pouring, a pitcher, measuring cup, or decanter can be used instead. Effective within a few minutes, the 2,4,6-trichloroanisole molecule is chemically similar to polyethylene and will stick to the plastic.

JacobH wrote:Without aiming to divert this post, is there any truth in Wikipedia’s cure?

I have heard that yes, the "cure" does in fact remove a significant amount of the TCA taint, but it has a tendency to replace it with a polyethylene taint.

heh anyboyd have a centrifuge at home?

would also make for an interesting sediment filtration method.

Glenn E. wrote:

JacobH wrote:Without aiming to divert this post, is there any truth in Wikipedia’s cure?

I have heard that yes, the "cure" does in fact remove a significant amount of the TCA taint, but it has a tendency to replace it with a polyethylene taint.

Ah yes, I can see that happening...

g-man wrote:heh anyboyd have a centrifuge at home?

would also make for an interesting sediment filtration method.

And possibly a way of increasing effective decanting time?

but it has a tendency to replace it with a polyethylene taint

I've not looked at it before, but the chemistry behind the polyethylene cure seems reasonably sound; and pure polyethylene should be odourless and tasteless.

Cling film is not always made of polyethylene, and is a bit fiddly - especially if pouring from a bottle.

I'm wondering where one might obtain a modest quantity of polyethylene granules (as used for injection moulding)..?

Tom

JacobH wrote:

g-man wrote:heh anyboyd have a centrifuge at home?

would also make for an interesting sediment filtration method.

And possibly a way of increasing effective decanting time?

but you wouldn't have to worry about murky port again!! =)

g-man wrote:

JacobH wrote:

g-man wrote:heh anyboyd have a centrifuge at home?

would also make for an interesting sediment filtration method.

And possibly a way of increasing effective decanting time?

but you wouldn't have to worry about murky port again!! =)

I'm fairly firmly in the "suck it through your teeth" school of thought, so it's not something that has particularly bothered me up to now

Soon it will be port extract that is mixed with distilled water...

heh at least then you can carry it on the plane without having to check it into baggage!

JacobH wrote:

Wikipedia wrote: One method of removing TCA from tainted wine is to soak polyethylene (a plastic used for applications such as milk containers and plastic food wrap) in the infected wine. The non-polar TCA molecule has a high affinity for the polyethylene molecule, thereby removing the taint from the wine. The surface area of polyethylene needed to reduce the taint to sub-threshold levels is based on the TCA level in the affected wine, temperature, and the alcohol level of the wine.

This can be done at home, as advocated by Andrew Waterhouse, professor of wine chemistry at University of California, Davis, by pouring the wine into a bowl with a sheet of plastic wrap. For ease of pouring, a pitcher, measuring cup, or decanter can be used instead. Effective within a few minutes, the 2,4,6-trichloroanisole molecule is chemically similar to polyethylene and will stick to the plastic.

Yes, it works. I've tried this with the US food wrap Saran Wrap, which is a pure polyethylene wrap. It certainly removed the TCA taint and improved the port, but still didn't leave it as it should have been.

Incidentally, it was Gould Campbell 1977 I was forced to do this with.

I had a quick look at the cling film in Tesco today - one brand says its PVC, another gave no clues..

Tom

I see a blind taste test coming. next time we have a bottle truly id'd as corked, we prepare regular and glad-wrapped versions of the wine, then pour one glass of one and two glasses of the other. Hand to someone who can spot TCA and get a verdict.

SushiNorth wrote:I see a blind taste test coming. next time we have a bottle truly id'd as corked, we prepare regular and glad-wrapped versions of the wine, then pour one glass of one and two glasses of the other. Hand to someone who can spot TCA and get a verdict.

It would probably be worth passing some non-tainted Port through the wrap, too, to see what effect that would have on it.

JacobH wrote:It would probably be worth passing some non-tainted Port through the wrap, too, to see what effect that would have on it.

Good idea.

I am skeptical of the whole thing.