I take a sip worth about £75. Having sheepishly declared my palate to be untrained, I furrow my brow as I search in vain for the apple skin. But I need no notes to detect the smoky, faintly medicinal flavour that makes Islay’s whisky an acquired taste — and gives it a cult following. It comes from the peat that is harvested from the island’s boggy moors and used as fuel for drying malted barley before distillation.