How Scotch Malt Whisky Is Made

Also see Part 2 - How Grain Whisky is Made and Part 3 - How Blended Whisky is Made

Scotch Malt Whisky is made from malted barley, water and yeast. The first stage of production is the malting of the barley. The barley is first steeped in tanks of water for 2 to 3 days before being spread out about 30cm deep on the floors of the malting house to germinate. To control the germination the  barley is turned 3 times a day, preventing heat developing and mould forming. When the maltster feels the time is right the germination is then halted, this is done by drying the malted barley in a kiln, this is identifiable by the distinct pagoda shaped chimneys which can be seen at every distillery.

Peat, a natural fuel cut from the moors of Scotland, is used to fire kilns in the drying process, along with more modern fuels. Smoke from the fire drifts gently upwards through a wire mesh floor to dry out the barley, and the "peat reek" imparts a distinctive aroma which contributes to the character of the final spirit. When dried, the malt is as crisp as toast.

The malted barley is then ground and mixed with hot water in a vessel. This process converts the starch in the barley into a sugary liquid known as wort. The wort is transferred to a fermenting vat, where yeast is added and the fermentation process converts the sugary wort into crude alcohol. This is known as wash.

Now comes the crucial process involving the distinctive swan-necked copper pot stills, where distillation separates the alcohol from the wash. Malt whisky is distilled twice, the first distillation taking place in a larger wash still, and the second in a slightly smaller spirit still.

The stillman raises the temperature within the wash still and gradually, the fermented liquid is heated and the alcohol in the wash vaporises. The vapours rise up the swan neck and pass over the head of the still, before being guided through condensers where they revert to liquid.

This liquid is then collected in a receiver before being passed into the second spirit still where the process is repeated. Much more control is taken in the second distillation as only the middle cut, of the spirit flow will be collected as new spirit. This takes place as the spirit flows through a spirit safe, where the stillman can observe, assess and measure it.

The skills of the stillman, required to judge the moment at which the Scotch Malt spirit is ready to be collected, are crucial to the art of distilling.

Once the quality has been approved, the malt and grain new make spirit is ready to be filled into a variety of specially selected oak casks for the long period of maturation in cool, dark warehouses. Now time begins to work its magic.

The quality of the casks is carefully monitored because the new spirit is to gain character and colour from the wood in which it rests. Some casks will previously have been used to mature oloroso, fino or amontillado sherries; some will have contained bourbon and some will be oak. The type of cask used for maturation will have been determined by the Master Blender who is seeking a particular character and continuity of the whisky.

Only after a minimum of three years maturation can the new make spirit be legally defined as Scotch Whisky. In practice, most Scotch Whisky matures for much longer, anything from five to thirty years and sometimes longer. It is during this time when Scotland’s cool, clean air steals through the porous oak of the casks and charms their contents, contributing further to the smooth and golden character of each distillery’s unique creation.

A proportion of the whisky in each cask evaporates annually and is lost to the heavens. This is known as the "angels’ share".

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