A Whisky Tour

Is this the most chemically complicated drink in the world? Victoria Gill attempts to unlock some of the mysteries of Scotch malt whisky.

- Victoria Gill

The finely-tuned process of Scotch whisky production is governed by its own law - the Scotch Whisky Act. There are 92 malt whisky distilleries in Scotland, and each one has a slightly different process - with different stills, malts and casks for maturation. Under the Act, Scotch whisky must be matured for at least three years, during which time the spirit reacts with compounds in the timber casks Chemists continue to study the complex effects of dilution on the sensory perception of whisky flavours.

When I worked in a tiny Edinburgh pub, I occasionally incurred the wrath of the regulars when the water jug sat on the bar wasn’t at room temperature by the time they wanted their whisky. So I’ve long been eager to find out if there’s any chemical truth behind this received bar wisdom, and similar whisky lore.

I’ve heard much postulating about ’releasing the flavours’, so during my visit to Edinburgh’s Scotch Whisky Research Institute (SWRI), I hoped the real experts might teach me how to make it - or fake it - as a whisky connoisseur, so that I could smugly explain to my friends in the pub exactly how one should dilute one’s whisky - and more importantly, why.

But embarking on a whirlwind tour of whisky chemistry raised far more questions than I could have predicted. Like the heady, aromatic spirit itself, it’s far from simple. There’s no single chemical composition to describe a whisky, so there’s no single way to explain what exactly happens in your glass when you add water, ice or even (heaven for fend) cola.

Making flavour