How to tell if an unknown wine will age well?

[californiagirl]

My guess would be depending on the level of tannins in a wine, you can guesstimate the ageability of the wine, since you don't have the background of the winery's past vintages. (Tannins are the tongue in cheek, banana peel pucker kind of feel.)

I only know of a few Merlots that I would personally age. (I have 1997 Mayacamas Merlot in my wine cellar.)