Peat, if you don't know, is decomposed organic matter—grass, heather, moss—that melds into a chunky, ever-deepening formation along the coastal, boggy lands of places like rainy, verdant Scotland and Ireland. It's amazing stuff—an ever-renewing resource—as it can plunge more than a meter deep and take up to a 1,000 years for the lower parts to form into hardened, coal-like, fossilized organic matter, which gets cut into brick-like shapes and used for heating homes. But the softer, newer top part—that's the stuff that holds the most moisture and smokes when you burn it. That's used in part to truncate the germinating of the little barley bits via heat and, in its most vital act, flavor the malted barley in Islay. And it's what makes it utterly different from any other Scotch whisky you will have.