I'm wondering if there are easily identifiable traits that different varietals possess. A couple of years ago I pretty much assumed that I could tell a Sauvignon Blanc from any other varietal, when I tried one that, to me, was very unexpected (but delicious), and closer to some Chardonnays that I'd had (Kalin Cellars 1992 S. Blanc).
I often wonder if a seasoned taster can really tell if a Zin is a Zin, and isn't tricked on occasion into thinking it's a Syrah or Cab.
Perhaps the traits become as clear as the differences between a lemon and a grapefruit, maybe not.
Maybe this has been covered elsewwhere, but could someone break down some things to look for in diff. varietals that make them unique from other grapes?