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The Making of Malt Whisky


Malt whisky is made by the Pot Still process involving four main stages.

scotch malt whisky, how it is made - MaltingMalting

The barley is soaked for 48 to 72 hours in tanks of water known as Malting steeps. Following the soaking, it is spread on the malting floor and allowed to germinate, which takes from eight to twelve days. The barley must be turned frequently to regulate the temperature and rate of germination. The malted barley or green malt is then dried in the malt kiln. During the drying process, peat will be burned, imparting its distinctive aroma.

scotch malt whisky, how it is made - Mashing Mashing

Mashing The dried malt is ground into grist, which is then mixed with hot water in a mash tun. The soluble starch is converted into a sugary liquid called wort. When the wort is drawn off, the remaining solid matter is used to make cattle feed.


scotch malt whisky, how it is made - Fermentation Fermentation

Once the wort is cooled, yeast is added and fermentation begins. The yeast converts the sugar into crude alcohol, which takes about 48 hours and produces a liquid known as wash.

scotch malt whisky, how it is made - Distillation Distillation

scotch malt whisky, how it is made - Distillation Malt whisky is distilled in large copper Pot Stills. When the wash is heated, the alcohol becomes vapour, rising in the still until it reaches a coiled copper tube or worm, where the vapour condenses into liquid state.

In the Pot Still process, two distillations occur. The first distillate produces low wines, which are then distilled a second time. Following the second distillation, the whisky is ready for its maturing in casks.

scotch malt whisky, how it is made - the Cask The Cask

Each Scotch whisky derives its distinctive flavour from a number of factors, among them the barley, the water, the peat used in the kiln or furnace, and, of critical importance, the cask in which it is matured.

scotch malt whisky, how it is made - the CaskA cask must impart a particular flavour and appearance to the Scotch without dominating. The two principal types of casks are the Oloroso sherry casks and the American oak bourbon casks. Whisky matured in former sherry casks is usually a darker colour than that matured in former casks. A barrel may be charred before the whisky is added in order to release vanillin from the wood. Some distilleries use the barrels as they are, and some distilleries build barrels using selected staves from several barrels. Casks may be used more than once if the whisky produced is especially good.

A single barrel of whisky contains 500 litres at its initial filling. After 15 years, and after the evaporation that occurs through the permeable cask as the whisky matures, the barrel will contain approximately 400 litres, or 600 bottles.

scotch malt whisky, how it is made - Proof of whisky Proof

The proof of a spirit is assessed through the use of the hydrometer, which determines the specific gravity of a fluid, in the case of whisky an assessment of the alcohol/water mixture. British “proof spirit” of 100 degree proof means that the fluid contains 57.1% alcohol by volume or 49.28% by weight at 51 degrees Fahrenheit.

When malt whisky is first distilled, it is usually 115-120 deg proof. For the British market it is generally watered down and bottled at 70 deg proof. Cask strength malt whiskies are those bottled without being watered down and are generally 100-110 deg proof (57-63% alcohol). Cask strength whisky may be drunk at full strength or diluted.

scotch malt whisky, how it is made - the Nosing glass Purists believe that for the true appreciation of Scotch whisky, one must use a nosing glass, which is like a small, narrow brandy snifter. Of course purists also believe that Scotch whisky should be drunk “neat” or with only a splash of water, never with soda or other mixers.



scotch malt whisky, how it is made - age of whisky Age

scotch malt whisky, how it is made - Bottling The stated age of the whisky is the age of its youngest component. Maturation ceases at the time the whisky is bottled, so a 12-year-old whisky will always be a 12-year-old whisky, even 12 or 24 years later.

Maturation, which occurs while the whisky is in wooden barrels, is a minimum of three years but is usually between eight and 25 years. Each year the barrel, which is permeable to air, loses about 2% alcohol, called “the angel’s share”.

The casks of maturing whisky reside in bonded warehouses, which are cool with an earthen floor to maintain even temperature and humidity. In 1994, bonded warehouses in Scotland held 2.5 billion litres of whisky, valued at the time at 20 billion pounds.