Released in the autumn of 1991 as a Japan-exclusive strategic product, Glenfiddich Classic Pure Malt was created with careful consideration of both the brand’s established character and the preferences of Japanese whisky drinkers. For its maturation, sherry casks were selected to shape its distinctive profile.
Single malts aged between 10 and 20 years were vatted together, then further re-casked and matured for an additional 12 to 18 months before being bottled. This expression has since been discontinued.
With its slightly reddish amber hue, Glenfiddich Classic Pure Malt is a medium-bodied single malt Scotch whisky, offering rich aromas of malted barley and red fruits, followed by a well-balanced and lingering finish.

From Glenfiddich Classic -THE WHISKY EXCHANGE-

It was an incredibly satisfying dram. I was deeply impressed when I tried the 15-year-old 50% ABV release back in the day, but this old expression was in a different league entirely. Of course, taste is subjective, so older doesn’t automatically mean better than the current lineup. But wow — it was superb.