Peat is a natural substance made over thousands of years from decaying vegetation. The northern part of Scotland is abundant with peat, as it was part of the vast Caledonian Forest for many thousands of years. Islands such as Islay have an abundance of peat thanks to seaweed, moss and other decayed vegetation found along the islands’ coasts.
Some distilleries use peat as the heat source for drying the barley, which gives the whisky a deep, smoky, and at times medicinal flavor. Peat is measured by ppm (parts per million) and the intensity of peat notes in whisky is generally derived by the treatment of the peat and the amount of time the barley is exposed to the peat smoke as it dries.
A peated whisky will lead to notes of sea spray, iodine, seaweed, medicinal, band-aid, or even a green and earthy bitterness. Barrel smoke will lead to a cleaner smoky note reminiscent of an autumn campfire, charcoal, or even ash.
For American single malts aged in charred barrels, the smoky notes from that barrel char should be a nice addition to the whisky’s complexity, but should in no way overpower the spirit. Some producers like Westland Distillery have released a peated American single malt using a majority of non-peated malt in their barley bill to ensure the peat doesn’t dominate. Other distilleries, like Santa Fe Spirits, embrace the smoke and use mesquite smoke to allow barbecue aromas to reign supreme in their Colkegan Single Malt. Corsair Distillery’s Triple Smoke American Single Malt is another standout in the smoke category, thanks to their use of peat, smoked beechwood and smoked cherry wood in the malting process.