I've only tried Glen Grant twice before - the standard 10 Year and a Berry Brothers & Rudd 1974 single cask. Neither has given me much of a basis for judging the distillery as a whole, so I came at this sample without many expectations. The WhiskyBase shop tossed a sample into one of my orders, so I gave it a try.
This whisky was distilled on July 5th 1990, filled into a hogshead, then bottled on September 23rd 2015 at 56.6% without coloring or chill filtration.
Archives Glen Grant 25 Year 1990/2015 Cask #15230
Nose: soft and subdued - lots of oak, something between floral and musky fruit notes (melon), glue paste, sweet malt, vanilla, roasted corn, grassy, citrus peel. After adding a few drops of water the oak becomes more expansive and wipes out some of the nuance.
Taste: big malt and cask sweetness up front, slightly tempered by soft oak tannins, becomes generically fruity around the middle, then fades into bittersweet hay and malt near the back. After dilution the generic fruitiness spreads out to encompass the entire palate, syncing up with the oak to give it an almost sherried quality.
Finish: carbonated fizzy water, oak, more generic fruitiness, generally bitter
On the face of it, this isn't a bad whisky. It reads somewhere between the grassier end of Speyside and the fruiter end of the Lowlands. There are no major flaws, it's generally enjoyable, and it's not terribly expensive for a 25 year old single malt in this day and age. Importantly, it's still available. At the same time, there are other single cask bottlings from the same distillery at roughly the same age that are 2/3-1/2 the price, which makes me pretty disinclined to recommend this one. It's not bad, but I feel like it should be better for the money.