If you're wondering what gives a lot of scotches their smoky flavor, the answer is probably more straightforward than you realize. Smoke makes it smoky. Specifically, peat smoke.
In this first entry of a regular series, I'll be breaking down a few different elements of how choices made during the production process of spirits end up producing a particular sensation or taste in the glass. Peat seemed to be a fitting place to start.
So first of all, what is peat?
Without mincing words, peat is decaying plant matter and soil mixed together into a homogeneous solid. Peat forms in wet bogs or mires, and is usually at least 30% dead plants by volume, according to people who know better than I do. One of the only things peat has going for it is that all of that dead stuff gives it a fairly high carbon content, so it can be used as a source of fuel.
Where scotch is concerned, that fuel is used to power a distillery's kiln. Barley grains are tricked into germinating by being soaked into water, which creates sugars that can be used for fermentation. However, before they can become full fledged plants, the process is halted by raising the temperature in the malting room and drying out the barley. In the meantime, the barley used for fermentation (and later distillation) will absorb the smoke from the kiln.
Why would anyone do such a thing?
You might ask why a scotch producer would ever send some poor soul out into the murk to cut a series of funky-smelling bricks when perfectly good fuels like oil, coal, or electricity are at hand. Most distillers asked themselves the same question as soon as alternatives became readily available.
On the Scottish mainland, where you could actually build railroads and transport fuel to businesses, there was indeed a shift to "unpeated" whisky. That's one of the reasons why the Speyside whiskies were able to create a lighter, fruit-forward style. However, islands like Islay were out of luck and had to stick with the peat, since it was often cost prohibitive to ship in anything else. Over time, these issues of infrastructure resulted in a difference in regional styles.
Of course, all of this is greatly oversimplifying centuries of whisky production, but they're the details as I understand them.
Peat in the modern era
Naturally, if citizens on the Scottish isles of Islay, Mull, or Skye can order from Amazon, we've clearly solved the problem of getting electricity to them. In the 21st century, no distillery needs to use peat. However, for scotch in general, peat became associated with a "traditional" style, and the smoke does indeed add a particular flavor. Today, each distiller gets to figure out for themselves how much peat to use and where they get it from. Some distillers contract out when it comes to the whole kiln smoking process. In these cases, their operations entail buying peated barley from somewhere else.
What's interesting is that not all peat is the same.
Just like wines have a sense of "terroir," the variations between climates, soil content, and dead stuff inside the peat all account for differences in what you'd taste in the glass. In other words, peat doesn't just vary in terms of its intensity, but also in terms of its quality. The peat of a distillery like Laphroaig always seems like the smoke you'd get from charcoal briquettes, whereas the peat of Lagavulin smells more like a beachside campfire to me. Highly-peated highland scotches often seem to have a dull earthiness / cigarette ash quality to them that I hardly ever care for.
Today, peat in scotch is a lot like the taste of hops in beer. Some people love it, and some people can't stand it. On one end of the spectrum, a distillery like Glengoyne states that it never uses peat, because it gets in the way of the spirit. On the opposite end, Bruichladdich's Octomore series can be peated to levels four times higher than even "heavily peated" Islay whiskies like Lagavulin and Ardbeg, placing those bottles solidly into the "I'll tell you when I've had enough" category of whiskymaking.
Where should I start?
A lot of folks are unsure of whether they like peat—or even scotch in general, since many scotches tend to be peated. Step one, I'd say not to throw the baby out with the bathwater. I'd suggest an entirely unpeated scotch like Glengoyne 10 or something where peat isn't a central component, like Glenfarclas 10. A blend like Dewar's 12 would also be a good choice. Scotch doesn't have to taste like peat as a default.
If you already know you like milder scotches, a great (and affordable) place to go is with the Johnnie Walker Black Label. Age stated at 12 years, it's a very quality blended scotch that makes peat a foundation of its flavor. If you'd rather stick with single malts, Highland Park 12 is another moderately-peated whisky that provides just a slightly stronger introduction.
If you want to jump in with both feet first, I'd go with Ardbeg 10 or Lagavulin 16. The former I like a little better and is a little cheaper; the later is more widely available (meaning you can often find it at a good bar or restaurant), but tends to be about 40% costlier in my neck of the woods.
So embrace the smoke. Or don't—that's fine, too. It's a big world out there.