When discussing the peat flavor in whisky, many people refer to “PPM,” or phenol parts per million—a measurement of how much peat smoke was imparted on the barley during the malting process. But the PPM of malted barley doesn’t necessarily correspond with how peaty the final whisky tastes. Using Port Charlotte 10 year old and MRC: 01 2010 as examples, Bruichladdich head distiller Adam Hannett explains how two whiskies that are made from barley malted to the same PPM level can end up tasting so very different.