A lot of mouth watering indicates a lot of acidity – it’s a natural reflex.
ACIDITY is really important in wine. Too much can of course be unappealing, but too little and a wine can feel flat or ‘flabby’; balance is the key. A simple way to test for acid is to see how much your mouth waters after you try a wine. A lot of mouth watering indicates a lot of acidity – it’s a natural reflex.  Tilt your head slightly forward after drinking the wine and see if you can feel the salvia running forward.  (Agreed on this being perhaps one step too far in a public bar. Perhaps leave this for if you’re taking a wine exam or wanting to write very detailed tasting notes!)