Single Malt Whisky

A Brief History

Uisge-beatha (Water of life) has been distilled in Scotland and Ireland for many hundreds of years. Early written records date back as far as 1405 in Ireland and 1494 in Scotland. Single malt whisky is mainly associated with Scotland, although there are Irish single malts.

Heavy taxes were levied against whisky in Scotland from the 15^th century forcing the production underground. Whisky was produced on illegal stills for hundreds of years after this. Most villages in Scotland would have a still or two producing whisky of a very similar quality to the whisky we enjoy today. An act of Parliament was passed in 1823 introducing heavy penalties against land owners found to have stills operating on their land. Commercial distilleries were encouraged and the distillation of whisky through the legal channels became profitable. The Glenlivet Distillery was founded in 1824 by George Smith making him the first licensed distiller in Scotland.

Methods of distillation changed over the years, with Aeneas Coffey working on a new design of continuous stilling, which was much more efficient, but the product lacked the taste from whisky made in the traditional pot stills. Merchants soon began blending whiskies from these continuous stills with the single malts; these were the early blended whiskies. International taste favoured the blended whiskies, encouraging the distillers of the single malts to supply the ever more lucrative export trade.

Single malt is today distilled in many countries around the world, including US, Canada, France, Sweden, Finland, Austria, Switzerland, Australia, New Zealand, India, Pakistan, Germany Japan Wales and South Africa. England’s only registered distillery is a new distillery in the Norfolk town of Thetford.

Production

A good supply of fresh water is crucial to making malt whisky. Many distilleries are located adjacent to burns or rivers, as immense quantities of water are used during the distillation process.

The water is added to barley to start germination; it is mixed with ground barley to form the mash and also used to dilute the whisky before maturation and again before bottling. Before being put into casks to mature, most malt whiskies are diluted to 63.5% alcohol by volume. Many modern distilleries use distilled water for the dilution processes bringing the bottled strength to 40 to 60% proof.

Malting

The process of germination of the barley is called malting. After 2 to 3 days the germination converts starch (which is insoluble in water and not available for fermentation by yeast) to fermentable sugars. In Scotland barley is spread over the malting floor and turned regularly. Traditional Scottish distilleries have a pagoda style vented roof in the malting shed. After 3-5 days the optimum amount of starch has been converted to fermentable sugars and the process is halted by heating. Many distilleries add peat smoke to the kiln at this stage to influence the flavour of the whisky. Islay malts which I personally do not enjoy use this method to produce a particularly smoky flavour, Laphroaig being the strongest.

Mashing

The malted barley is now milled to a fine flour or grist and is transferred to large metal kettles known as mashing tuns. Hot water is added to start the extraction where the sugars and enzymes are dissolved in the grist. The sugary liquid which is left is known as wort. Most distillers will complete this process 3 times to extract as much of the fermentable sugars as possible. Anyone living near to a distillery will recognise the delicious smell from this process.

Fermantation

The wort is now transferred to a large container called a washback where the yeast is added. Fermentation will now take place where the yeast will feed on the sugars producing alcohol and carbon dioxide as a by product. The process up to this point is very similar to the making of beer. After 3 days or so the alcohol content is usually 5-7% by volume. The liquid is known as wash at this stage.

Distillation

The wash is transferred to the copper pot still for distillation. Boiling causes the alcohol to vaporise and it is collected in a condenser which is submerged in cool water. The cooler temperature causes the vapour to become liquid once again where the alcohol content will dramatically increase to 20-40%. This liquid is known as low wine. The low wine is distilled 2 sometimes 3 more times to form the “new spirit” which will now have an alcohol content of 60-70%. Stills eventually wear out and precise measurements have to be taken to ensure that the new stills are an exact replica of the old one. The reason for this is that the belief is that the eventual whisky will gain its body and “mouth feel” from the size and shape of the still.

Maturation

Malt whiskies are matured in oak casks for up to 20 years, but the law states that Scotch whisky must mature in casks for a minimum period of 3 years. During the maturation period the whisky will continue to change and develop. Depending on ambient conditions in which the casks are stored, evaporation will take place at varying rates, usually about 1 or 2%. This is known as the “Angel’s share”. Much care is taken with the choice of casks for maturation, as this will have a profound effect on the eventual taste of the whisky. For example, an American Bourbon cask will give a vanilla type of flavour, while sherry casks will have an effect on the colour of the whisky. Sherry casks were originally used when sherry was shipped to Britain in casks. It was more expedient to re-cycle the casks in the distillation process than to return them empty to Spain. Due to the use of stainless steel shipping containers instead of oak casks, The Macallan distillers actually manufacture their own casks and lease them to sherry makers for sufficient time for the required properties to be retained by the wood. Madeira, port, rum and cognac casks are also used.

Bottling

As the name would suggest, a bottle of single malt whisky must contain only one whisky, distilled at a single distillery. Vatted malt, blended malt or pure malt is single malt from more than one distillery. If a grain whisky is introduced to the equation, the result is blended whisky. Cask strength or un-diluted whisky is becoming more popular and often boasts an alcohol content of around 60%. Most whisky however, is diluted to around 40-45%. Unlike wine, whisky will not mature further once it has been bottled.

Storage

Whisky should never be stored in direct sunlight or near to a source of heat, as  evaporation could occur. Corked bottles should always be stored upright, as prolonged contact with the whisky will eventually cause the disintegration of the cork, having an adverse effect on the taste of the whisky. The only question I have of myself at this stage is, why would one want to store whisky for such a long period as to have an effect on the cork. I think I might just have a wee dram now.

Slainte (Cheers)