That is why I tried two undisclosed Macallan from IBs today, this one and https://www.whiskybase.com/whisky/34926/pride-of-strathspey-25-year-old-gm and an young Cadenhead dumpy https://www.whiskybase.com/whisky/42314/macallan-1979-ca
This Glen Gordon is quite an odd one: Besides the typical Macallan sherry and creaminess it is full of strange off-notes that I never experienced in a Macallan before. A lot of these nasty flavours remind me of rotten things, rotten oranges, rotten spices... Besides this there are heavy tannins that dry out this dram unpleasently. This is not a Macallan I like!
So, could it be that this Macallan fell victim to a rotten sherry cask? You know when Spain stopped exporting its sherry cask-wise to England (to be bottled in London) the Scottish distillers faced a problem. They needed sherry cask-matured whisky for some of their blends and brands (like Macallan) and now they had to import these casks empty from Spain. In the beginning this took them somtimes weeks (if not months) after emptying the casks and as the weather usually is very hot in Spain the sherry-soaked wood began to rot under these conditions.
That is why they started to burn sulphur candles within the casks to kill all the bacteria that caused the rottening, with the unpleasant effect that all the whisky from these casks now is heavily spoiled with sulphur flavours. And sulphur as the smell of hell does not work very well (within the beloved drink of the angels), at least not for me!!!!
All in all, this Glen Gordon is not a very nice Macallan and I would not suggest to open your bottle unless you want to demonstrate the effect of (slightly) rotten casks to your friends. But at least you can tell them this nice little story...