Friends Don't Let Friends Drink Bad Wine

My wife and I have an secret hangover prevention system. Here's how it works:

I'm usually the one fetching our drinks. I'm happy to do it. It's chivalrous, I like taking care of my lady, and, well, I'm taller than most people, so bartenders have a hard time missing me. If we're at a function and wine is being served, I'll sample everything before handing it to my wife.

What I'm looking for isn't aroma, body, or quafability - no, no, no - I'm doing this for safety. So, I look for tell-tale signs of unusually high residual sugar and overmanipulation. Too much messing around. And messing around rarely makes good wine.

When I hand it to my wife, it gets delivered with a hand signal. Like a catcher signals the pitcher. The number of fingers I hold up represents the number of glasses of what I'm giving her she can safely consume in that evening. Sometimes it's good stuff and I just put my hand out palm facing up in a "whatever, go crazy" gesture. And sometimes I make the index finger-to-thumb zero sign meaning I'll get us a couple of beers in a sec.

It's a safety net.  It's the insurance policy against "Oh-my-God...I feel like I got hit by a truck...and I only had two glasses of wine."
So, what does residual sugar taste like?  Better yet, what does messing around taste like?
Part of it is having an experienced palate.  In this case, experience comes with a lot of headaches.  But there's another way to develop this.  By example.
Go to Trader Joe's and get yourself a bottle of Charles Shaw Chardonnay (aka Two Buck Chuck).  Then find yourself another respectable Chardonnay like this one.  Keep them at room temp and taste them side by side. 
  • Does one taste a little bit cidery?
  • Does one have a bit of effervescence?
  • Is your mouth coated with an aftertaste with one more than the other?
  • Does one have a bit of a chemical smell?
  • If you swish them around your mouth, is one more sweet?
You're getting the idea.  Next time you're at a function, practice safe drinking with the one you love.