What is peated whisky? An introduction and short history

Peated whisky is given its flavour by compounds called phenols, which are absorbed by the malted barley as it dries. The strength of this flavour depends on how long and intensely the barley is exposed to peat smoke and the characteristics of the peat itself. But where did this popular trend begin?

We’ll start by turning to the acclaimed whisky writer Michael Jackson. It was he who once said there are devotees to whom ‘Islay single malt’ form “the most blessed incantation in the language of whisky”. Indeed, the whisky produced on Islay enjoys a reputation of unrivalled fervour, and has done for some time.

But Islay whisky and its broader stylistic traits weren’t always unique, nor even always revered. Despite considerable variation, Islay whiskies generally fall under the category of ‘smoky malts’. But smoky malts aren’t exclusive to Islay, and certainly weren’t so in the past.

The defining process

Today, distilleries largely rely on commercially malted barley. In days gone by, however, they necessarily had to malt their own. Malting makes the starches within barleycorns soluble so that the sugars may be converted into alcohol. In other words, malting tricks barleycorns into thinking spring has come. Barleycorns are steeped in water and allowed to germinate before the process is halted in the kiln.

Peat was once the primary domestic fuel in Scotland, used to fire distillery kilns throughout the country. Composed of decayed vegetation such as moss, grass and tree roots, it is often thousands of years old and produces an especially aromatic smoke. To a point, it has a considerable influence on malt during kilning, imbuing it with compounds called ‘phenols’. Typical flavours include tar, ash, iodine and smoke.

Peated whiskies weren’t to everyone’s liking and even today the audience is divided. And yet due to a lack of alternative fuel sources, whiskies using entirely peated barley were once the mainstay of the industry. This was especially true of the remote Highland and island distillers. That was, until the introduction of coal and, by continuation, coke.

The Lowlands and Speyside were the first to convert. The development of rail transport during the 1960s in Scotland led to the availability of coke. Coke burns more evenly, more consistently and with considerably less smoke than peat, and so these regions were the first to realise the potential of un-peated whisky.

Standing by the peat tradition

Others followed, but not all. Islay to the west, Orkney to the north and several mainland distilleries held fast to tradition (albeit initially out of necessity) by continuing to use varying proportions of peat during the kilning process. This maintains a traditional and now largely unique style of whisky brimming with variation and flavour. And those still with their own maltings such as Laphroaig on Islay, Highland Park in Orkney and even Balvenie in Speyside go one step further by peating relatively small quantities of barley for their own use.

The whisky drinker eventually makes his or her way to peated whisky, so the phrase goes. An exploration of those lighter, un-peated expressions common to the mainland generally comes first. But why should this be? As the author and Master of the Quaich Charles MacLean notes in MacLean’s Miscellany of Whisky: “Perhaps the big Islays, the smokiest of all malt whiskies, recollect the whiskies of the past. And perhaps one of the reasons for their current popularity is their ‘authenticity’, their ‘heritage’. An atavistic folk memory, like candles and open fires, Christmas trees and stormy nights.”

Perhaps it is fair to say, then, that peat is so much more than a stylistic trait or a differentiating factor enticing whisky drinkers to test their mettle. It is much more, indeed, than a simple addition of ‘smoky’ flavours which overwhelm all others. Peat was and still is an entirely defining aspect of Scotch whisky, and we should approach it with reverence, an open mind and a whetted palate from the very start of our journeys therein.

Five peated whiskies to try


A classic: Laphroaig 10

A newcomer: Ailsa Bay

A little smoke: Highland Park 12

A lot of smoke: Octomore 8.3

A world whisky: Amrut Peated