The label of my bottle of Bowmore Darkest single malt Islay Scotch (one of the old bottles containing 14-year old whisky, instead of the current -- and more expensive -- 15 year old version) has a little medallion in the center that says "From the No. 1 Vaults of Black Bowmore." The No. 1 Vaults are Bowmore's premier aging cellars, and Black Bowmore is a legendary special bottling released in 1964. It had been distilled in the 1920s and aged for 20 years in a first-fill Oloroso Sherry hogshead. That hogshead then began to leak, and the whisky in it was racked into Bourbon barrels to age for another 20 years. The 40 years of aging (20 of which in a hogshead which had contained the darkest of all the Sherry varieties) produced a Scotch that was opaque and dark as night. Supposedly, bottles of Black Bowmore come up for auction every now and then; and they typically go for astronomical sums.
This Darkest doesn't have quite the degree of color that Black Bowmore did, but it is plenty dark. It was aged for 12 years in ex-Bourbon barrels and then finished for an additional two years in ex-Sherry casks. I don't know what kind of Sherry those casks were, but I would bet that it wasn't fino -- the casks impart a great deal of color, sweetness, and flavor to the whisky; and a delicate Sherry like fino could not have had that kind of an impact. Bowmore's stills are relatively squat, and their charges are relatively heavy, both of which tend to reduce the copper contact during distillation. This makes the spirit heavy and pungent, and it takes a heavy and pungent Sherry like Oloroso to compete with it. And it does compete. The idea of a Sherry-finished Islay struck me as more than a bit odd when I first heard of it, but I think that it works with this whisky. The sweetness of the Sherry softens the smokiness and brininess of the Scotch, and it gives the whisky another dimension. The problem I have with most peaty Islay whiskies that I've had is that my enjoyment of them is mostly intellectual. Bowmore Darkest offers a good deal of sensual enjoyment, too.