What determines the taste of a whisky ?

Peat Smoke

When the malted barley is dried, peat may be added to the firing, or peat may even be used as sole fuel, in order to smoke the malt. Depending on how much the malt is 'peated', the whisky will develop a more or less peaty taste.

Water

Each distillery has its own water supply, usually a nearby loch (lake) or a spring. Some distilleries have very peaty water, others have quite clear water, thus yielding a different taste.

Stills

Each distillery has its own design of pot stills. It is generally assumed that the shape of the stills has a strong impact on the taste of the whisky, thus if new stills are installed, care is taken that the shape of the old stills is preserved as precisely as possible. On the pictures you can compare the stills of Cardhu (left), Laphroaig (middle) and Bowmore (right).

[Cardhu Stills]  [Laphroaig Stills]  [Bowmore Stills]

The stills of Cardhu and Bowmore look quite similar, but the necks of the Cardhu stills seem to be more slender. At Laphroaig different designs are used for the wash stills (in the background) and the spirit stills (in the foreground).

Casks

Essentially two types of oak casks are used for maturing: american casks, which previously have been used for maturing Bourbon, and spanish casks used for maturing Sherry. Whisky matured in Bourbon casks will retain a light golden colour, while maturing in Sherry casks will yield a darker colour -- whisky matured in a Sherry cask for 30 years can be almost black. Also the aroma of whisky matured in Sherry casks will be somewhat sweeter and more sherry-like, of course.

Oxygen

Whisky matures only in the cask, not in the bottle, contrary to wine. In a sealed bottle, whisky will keep very long time without changing its taste. However, once opened, the aroma may degrade due to oxydation on a timescale of several months - at least this is what some people say.

The observer

There are many tasting notes available for individual whiskies, and if you compare some of them, you will find that different persons can have quite different opinions on the taste of a distinct whisky. Do not rely on others -- collect your own experimental data!