After years of critically tasting & assessing whiskies in quite serious and deliberate assessments, I have reached the conclusion that only about 15-20% of whiskies improve
For the rest, water pretty much seems to kill the dram dead. Best example is Macallan Fine Oak 18yo. Adding water to this almost makes it unpalatable. I was reviewing this whisky for an Australian magazine, and - after adding water - my tasting notes read, "Yuuurrrrkkkkkk". My sentiments were shared with two others on the tasting panel.
If I'm going to sit down and enjoy
whisky at my own leisure, I am no longer interested in adding water - based on my experience that there is an 80% chance I will ruin the dram.
It is true that adding water sometimes lifts the nose and reveals elements that may not have been obvious beforehand. But then the palate is forever affected. You can't take the water back out again!
Most of the whiskies we drink are 40% alcohol by volume. Put another way, they are already 60% water. Why add any more?