This malt is so-called because, after maturing in Bourbon casks, it spends time in Oloroso and Pedro Ximénez sherry barrels, a process which means the whisky brings something from all three kinds of wood.
Sometimes you'll taste spice and coconut from the Bourbon. Other times, the cigar box and chocolate of the PX will dominate. And nearly always, the dried fruit and nuts of the Oloroso casks is there, giving a rich, mellow, balanced, relaxing-in-your-favourite-armchair feel to your dram.