A question about "Tannins"

[Jason]

Tannins confuse many people. You are correct in saying they are a component in all red wines. Phrases like "well integrated" mean they are in balance with the other taste factors. A wine can have gobs of tannin and still be balanced if the others pieces are all there in proper amounts.
Even the experts can not agree on the relationship of tannin and aging. Its basically accepted that a certain amount is needed for ageworthiness, but some argue that wines that are tannic monsters will never harmonize because they are poorly made to start with and time will only make the wine older, not better.
This is where the subjective part starts. Many people find a wine writer that jives with their own palate, and then follow that writer's views and predictions for future potential.
To confuse matters further, tannins come from grape skins and oak barrels both. In pro tasting the identity of tannin source is a piece of the puzzle the taster must find.
The ability to "taste through" the tannins and peak into a wines future is very tough indeed. This is why wine buyers who are tasing barrel samples (and buying sometimes years ahead) get paid very well. If they forecast incorrectly, they then have hundreds of cases of bad wine to sell.
The best descriptor I've heard for tannin is when you place an aspirin in your mouth and can't find your glass of water. That taste is pure tannin.