Insider knowledge: Glenfiddich 18 Year Old Excellence whisky is named whisky by virtue of the fact it's from Scotland. If distilled in America the spelling would be Glenfiddich 18 Year Old Excellence whiskey, as opposed to whisky.
I recently purchased a bottle of the 18 year old glenfiddich. It is by far one of the smoothest, easiest sipping whiskys I have ever had the pleasure to taste. I also purchased the 21 year old and have found the 18 year old is actually better.
D. G. Duggar