Islay Scotch cocktails.

Islay is a small Hebridean island with ten distilleries and the most distinctive whisky in Scotland: single malt that tastes of peat smoke, seaweed, iodine and salt. Some people cannot stand it and some people drink nothing else. In a cocktail it is a seasoning — a float, a rinse, a quarter-ounce — and in that role it makes drinks nothing else can.

What is Islay scotch?

Single malt Scotch whisky made on Islay (pronounced EYE-la), one of the five protected whisky regions. The island is small — about 3,000 people — and famously peaty, because its barley was traditionally dried over peat fires, and the phenols from the smoke stay in the spirit. The result is the most heavily peated whisky in the world, measured in parts per million of phenols: a typical Islay malt sits at 35 to 55 ppm, the extreme bottlings well over 100, and most mainland Scotch under 5.

Not all Islay whisky is smoky. Two of the ten distilleries make mostly unpeated spirit, and the peated ones range from gentle to ferocious. "Islay" on a label promises the island, not a fixed level of smoke.

How it's made

As any single malt: malted barley, mashed, fermented, distilled twice in copper pot stills, aged at least three years in oak. The difference is the malting. Barley is steeped, germinated and then dried in a kiln, and on Islay that kiln traditionally burns peat cut from the island's bogs. The longer the barley sits in peat smoke, the more phenols it absorbs, and the distiller specifies the level. Maritime ageing — warehouses on the shore, salt air — is credited with the seaweed and brine notes, though how much it really contributes is debated.

Most Islay malt is aged in ex-bourbon casks, which let the smoke show; sherry-cask Islays are richer and darker and very sought after.

What it tastes like

Peat smoke first — bonfire, tar, creosote, a medicinal, iodine edge — then sea salt, seaweed, wet rope, and under it the malt's sweetness: honey, vanilla, pear. The southern distilleries are the heaviest and most medicinal; the northern ones lighter and more floral. With age the smoke softens and the fruit comes forward. Add a drop of water and the aromatics open noticeably.

Styles worth knowing

Style	Distilleries (examples)	In a drink
Heavily peated, medicinal	Laphroaig, Ardbeg, Lagavulin	Penicillin float, a rinse, a Smoky Martini
Peated, balanced	Caol Ila, Bowmore, Kilchoman	A smoky Rob Roy or Old Fashioned base
Lightly peated or unpeated	Bunnahabhain, Bruichladdich (classic)	Any scotch cocktail; sipping
Extreme peat	Octomore, Port Charlotte	Dashes only; sipping for the devoted
Sherry-cask Islay	Special releases from most of the above	Neat

Which bottle to buy

For cocktails, a 10-year from one of the heavily peated southern distilleries. You will use it in quarter-ounces, so a standard bottle lasts, and the point is intensity. For drinking neat, a balanced middle-weight Islay at 12 to 15 years is the gentler introduction. Avoid paying for age in anything you plan to mix.

Using it in drinks

Two famous uses. The Penicillin — blended scotch, honey, lemon, ginger — finishes with a quarter-ounce of Islay malt floated on top, which is the single best demonstration of what the stuff does. The Smoky Martini is gin with a bar-spoon of Islay in place of vermouth. Beyond those, a rinse of Islay in an Old Fashioned or a Rob Roy adds smoke without taking over, and a split base — half blended, half Islay — makes a Blood and Sand or a Scotch Sour considerably more interesting.

It also works in tiki: a quarter-ounce in a Mai Tai or a Daiquiri is a known trick. Smoke and lime get along.

Substitutes

Any heavily peated malt from elsewhere — Talisker, a peated Highland or Speyside, a peated Irish or Japanese whisky — does the same job. Mezcal gives smoke of a different kind and works in most of the same roles. For a rinse, a few drops of liquid smoke in a bland whisky is a cheat that works. Unpeated scotch does not substitute; the smoke is the point.

Storage

Upright, cool, dark. Islay malt is robust and an open bottle keeps for years, though the smokiest notes fade a little in a bottle that has been nearly empty for a long time. Decant into a smaller bottle if you are nursing something old.

Questions

Is all Islay whisky smoky? No. Most of it is, and the famous names are, but two distilleries make mainly unpeated spirit and the others vary in intensity.

What is peat? Partly decomposed plant matter from bogs, cut and dried as fuel. Burned under malting barley it gives off phenol-rich smoke that the grain absorbs.

What does ppm mean on a label? Parts per million of phenols in the malted barley — a measure of how heavily peated it was. The number in the finished whisky is lower.

Can I use Islay as the main spirit in a cocktail? Yes, with care: a Rob Roy or an Old Fashioned on Islay is excellent if you like smoke. For most drinks a float or a split base is wiser.