What Is Peat, And Why Does It Turn Some People Off?

By Richard Thomas

One of the signature flavor characteristics routinely associated with Scotch whisky is smoke, specifically peat smoke. Not all whiskies are smoky; in fact, most of them aren’t. Many of the most famous have at least a wisp of smoke in them, however. Islay, arguably the most famous of Scotch whisky regions, embraces peat smoke as a key element in its identity.

Some whisky enthusiasts are devoted to peaty flavors, with the diehards are sometimes called “smokeheads.” From our “Talks Scotch” interviews, for example, author James Holland prefers smoky Islays, and model Kelly Klein is such a smokehead she is interested in little else. Yet this same flavor profile is a serious turn-off, serving as a serious bar to entry for many drinkers, so much so that even some Scotch fans can’t stand it.

As for myself, I occupy a happy middle ground where I enjoy a fine smoky, oily, saline Islay whisky, but at the same time am very partial to a Speyside Sherry bomb. I’m not among those who are polarized by peat, a point that leads me to wonder why so many are.

What Is Peat?
Peat is essentially baby coal, partially decomposed vegetation that has collected in cool, wet bogs. There it is compressed and marginally preserved, becoming a spongy, carbon-rich substance. For millennia, humans have cut peat out of the ground, dried it, and burned it as fuel.

In Scotland, where roughly a quarter of the country is covered by peat deposits, burning peat was quite common, and this is how it found its way into the whisky industry. Peat was often burned to fire the stills, but in particular the malting floors. Malting barley is a key step in both making beer and whisky, and the barley absorbs some of the peat smoke in the process. Those flavors then make their way into the new make spirit during distillation.

Pot still design influences how much of those flavors transfer into the whisky and what form they take, as is the case with so much of the flavor in new make whisky. As a rule, tall, slender still necks and heads lead to clearer, purer spirit, and squat stills produce a heavier new make. When it comes to peat and stills, take a gander at Lagavulin’s stills (right) and ponder how that whisky turns out.

In modern times, more efficient energy sources have replaced peat as a fuel source. For example, coal replaced peat in firing stills, which in turn was replaced by steam boilers fired by oil or natural gas. Nowadays if a malting floor is heated using a peat fire, it is because the smoky imprint is intended.

Measuring Peat
The extent to which peat smoke has impregnated the malt and found its way into the whisky is actually measured, this in terms of PPM, or phenol parts per million. Unpeated malt rates a 0.5-3 PPM, whereas the typical Islay whisky rates between 50 and 80 PPM. After distillation, the PPM will drop to between 30 and 50% of its original level. For example, Ardbeg peats most of its malt to 54 PPM, but by the time the new make comes out of the still this has dropped to between 17 and 24 PPM.

The peatiest whiskies have PPM numbers in the triple digits, such as Ardbeg Supernova, reportedly peated to 100 PPM. Yet the bad boy of peat is Bruichladdich Octomore. While PPM levels fluctuate from one year to another, the malt used routinely has PPMs in the 160-range, and one release was peated all the way up to 258 PPM!

Why So Much Fuss?
Clearly a whisky peated up to over 250 PPM is not going to be for everyone, even those who like a little smoke in their dram. Ultimately, peat is one of those issues where it’s all about different folks, different strokes. Just as some people love bourbon, but dislike Scotch, some people can like Scotch while disdaining those peated whiskies within it.

This would all be well and good, except that Scotch is one of those things that practically begs for diehard snobbery, something easily demonstrated by bringing up the subject of spelling whisky vs. whiskey. There are a small, loud group who seize on that and declare anything with the “e” isn’t really whisk(e)y in the first place, a statement that has more to do with their views on the supremacy of Scotch whisky with international spelling rules. If that is the way some people feel about a word, imagine the stance of a one of these folks who is a smokehead as well, and it’s not hard to see how the lines got drawn.