Whisky-making is one of the most elegant of all industrial processes. Its essential shape — grain, water, yeast, still, cask — has changed remarkably little in centuries, yet within that simple structure lies an enormous variety of technique and philosophy.
Malting
The process begins with barley, which is soaked in water for several days to encourage germination and then dried in a kiln. In some Scottish distilleries the drying is done over peat, giving the malt — and therefore the finished whisky — its characteristic smoky flavour.
Mashing and fermentation
The malted barley is ground into grist and mixed with hot water in a mash tun, extracting the sugars in the grain. The resulting sweet liquid, called wort, is transferred to a washback and combined with yeast. Over several days the yeast converts the sugars into alcohol, producing a coarse beer known as wash.
A whisky's character begins long before the cask — in the barley, the water and the shape of the fermentation.
Distillation
The wash is distilled — typically twice for Scotch, three times for Irish — in tall copper pot stills. The distiller carefully selects only the heart of the run, the middle cut of the second distillation, as new-make spirit fit for maturation.
Maturation and bottling
The new-make spirit is filled into oak casks and left to mature for many years. When it is ready, it may be blended with other casks, reduced in strength with pure water and bottled. Only then, in the words of the industry, is the whisky truly made.