Distilling

Islay distils twice, not three times. The wort from the mash first becomes a weak, raw alcohol in the wash still. Then a second distillation follows in the spirit still, producing the clear new make spirit. A third distillation, as some Irish distilleries run, is unknown here.

How intense the smoke ends up tasting also depends on the shape of the stills. Caol Ila distils in three wash stills of 20,000 litres each and three spirit stills of 12,000 litres each. All have a bulbous, onion shape with no waist and long, downward-sloping lyne arms. This cools the vapour quickly and produces a rather smooth spirit. Bruichladdich, on the other hand, favours tall, pear-shaped stills. Two wash stills there hold around 12,000 litres, two spirit stills around 11,000. There's also an adjustable Lomond still for special bottlings.

Every still on the island is made of copper. Copper strips unwanted sulphur compounds from the vapour and makes it smoother. There's no column still on Islay, of the kind that runs continuously for grain whisky or bourbon. Single malt demands a single batch in the pot still, with a pause and a fresh charge after each run.

At the end of every second distillation, the stillman splits the run into three parts. The foreshots and the feints contain too much methanol or fusel oils. They're discarded or held back for the next run. Only the heart in between, the heart run, ends up filling the cask, usually at around 60 to 70 percent alcohol.