The only time I have had a clean example of it was at the judging training conducted after a winemaker magazine conference. The chemicals used were in a test kit that was produced in Britain.@Rice_Guy What does Acetalaldehyde taste like?
* at low levels, a pleasing apricot note, mild, mainly on the back of the throat.
* at high levels a harsh burn on the back of the throat, it is a second wave after sweet notes on the tongue, it can be powerful enough to cover fruit aromatics, it should wash out of the mouth faster than a tannin and slower than an acid.
* google would tell me that an average population will pick it up at 100 ppm which is one tenth the detection level for clean ethyl alcohol
A side note, if you get to taste clean example of TCA it is nasty, I had that taste in my mouth for half an hour, (only do that one followed by a break)