A cult classic, with brands such as Ardbeg, Laphroaig and Lagavulin making up the mainstays of this smoky, peaty whisky flavour profile, measured in PPM. This is one of the ways in which distilleries can give their whisky a unique character. Crudely, PPM is a measure of ‘peatiness’ in whisky. The phenols come from the smoke of a peat fire and are absorbed by the malt whilst it is drying, leading to different levels of peatiness in a whisky depending on the length of time the smoking takes place for.