FoodBanter.com - View Single Post - How to determine your TCA sensitivity threshhold

Hunt

In article >,
says...
>
>
>I would like to find out what my TCA sensitivity tresshold is
>(wouldn't you also, by the way)?
>
>I have read that some folk are sensitive to concentrations as low as 1
>ng/l (nanogram per liter), or possibly even lower, and that others
>couldn't detect TCA unless they were swimming in a vat of the stuff.
>
>Wondering where I can get some ready-made TCA solutions of different
>concentrations in the range found in corked bottles.
>
>Alternative, I guess we can start with, say, a 1000 ng/l solution and
>dilute it by half, then by half again, etc. I am just concerned that
>the serial dilution approach increases the error as one goes on, which
>could be significant if doing it with bad equipment.
>
>While we are at it, would the serial dilution be acceptable if done
>using a 100 ml volumetric flask and a 200 ml volumetric flask?
>
>I would take 100 ml of concentration X, put it in the 200 ml flask and
>fill to volume, resulting in 0.5X. Then, take 100 ml of 0.5X, put it
>in the 200 ml flask and fill it to volume, resulting in 0.25X, etc.,
>etc.
>
>First things first, where can I get a solution of known concentration
>of TCA (in water and suitable for human sipping and spitting)?
>
>Thanks.

As far as one's sensitivity to TCA goes, it is an interesting
situation/problem. Both my wife, and I, are very sensitive to it. We usually
agree 100% on its existance. Maybe because of a great olfactoray ability, I
can often pick it up, when a waiter passes by with wines b-t-g in a restaurant
filled with other odors. However, there are times, that I am not 100% sure and
ask for her validation. If I have detected it, she has always confirmed it.

On the palete, I usually find a higher concentration of acid, and very muted
fruit. This is most often used as the confirmation to the nasal perceptions.
This is less than perfect, if I do not have some reference for the particular
wine. It also seems better suited for whites, than for reds. As many reds have
a dusky, musty, earthy quality, I have to really concentrate with some of them
to make sure that it is not "Rutherford Dust," or similar, that I am
experiencing.

For a purely scientific standpoint, I think that Mark Lipton covered most
bases.

As a total side-note, if I encounter a bottle, that I feel is "corked" at a
tasting, I offer samples of it to my guests, so that they will come to know
the characteristics next time.

I've got a bottle of Talbot Chard to return, because of TCA. This was one
bottle out of six from the local Costco, plus one bottle of Meursault from
K&L, again, one of six. Fortunately, I've only had a few reds, over the years,
and unfortunately, most were acquired too long before to think about returning
- imagine finding the receipt for a bottle of whatever, six years down the
pike.

Hunt