I wasn't a scotch fan until I tasted Scottish whisky aged in Spanish sherry casks. Traces of the fortified wine in the oak lend these spirits a delicate sweetness. The exemplars of the style come from the Macallan distillery, along the Highlands' river Spey, which has been making a line of exclusively sherry-oaked whiskies since farmer Alexander Reid founded it in 1824; Macallan continued the line even after many others switched entirely to less costly, plentiful bourbon barrels in the mid-20th century. Because the barley used to make The Macallan is malted with wood fire, rather than peat, the scotch's subtleties aren't obscured by the smokiness that moss can impart.
The 12-year-old Macallan ($50), fragrant with vanilla and ginger, has a light, nutty toffee flavor. Longer in oak, the darker 18-year-old Macallan ($200) hints of raisins, citrus, and wood smoke. At 30 years old ($1,134), the pricey but extraordinary scotch takes on a mahogany hue and a lengthy finish. I'm mesmerized by its nutmeg, clove, orange, and fig flavors. I found out last summer I'm not alone: The French Laundry's Thomas Keller is also a fan. The occasion was the launch of the restaurant's spirits program—after 30 years of beer and wine only, they now serve liquor. The only single malt scotches on the menu? The Macallan, many from the Fine and Rare series: limited-edition, single-cask scotches named for the year they were barreled. Distilled during wartime when wood was scarce, The Macallan 1948 ($17,500) is a touch peaty but surprisingly lithe, with lemon and apple flavors that belie its 50-plus years in the bottle. Each sip is a joy.