Historians agree that whisky production, albeit on a small scale actually began in Ireland somewhere around or before the twelfth century and was brought across to Scotland somewhat later. The first recorded instance of a grain spirit in Ireland dates back to 1172 and it is not till 1494 that a firm record exists of the same spirit in Scotland. It is worth noting that until about the 1950s all malt distilleries would carry out the entire process on the site - malting, fermenting and distilling. Now only a few distilleries have their own maltings.
Many distilleries began their lives on farms. The distilling season began after the harvest and continued until late April. Until modern times this cycle was followed by all distilleries and even now there is a 'silent season', usually in August when many distilleries are closed.
As has been stated above, the process of malting converts the plain barley grain into malted barley and by so doing greatly changes its chemical makeup. The barley is first soaked for between 48 and 72 hours in tanks or 'steeps' and allowed to germinate. Germination releases heat which has to be controlled in order to keep the temperature around 60 deg F/16 deg C and avoid the barley killing itself from its own generated heat. Traditionally the malting barley was drained and spread out over a large floor then turned regularly by hand with rakes or shovels. This was repetitious and arduous work, leading sometimes to a repetitive-strain injury called "monkey shoulder". More recent maltings designs employed either mechanical rakes (Saladin box) or large revolving drums to achieve the same effect.
The fully germinated malt is next transferred to the kiln for drying on a mesh over a fire containing a certain amount of peat, thus contributing to the peaty taste evident in many malt whiskies. Traditional malt kilns draw the hot air from the peat furnace through the malt by way of a chimney effect generated by the characteristic steep roofs and pagoda heads of many Scottish distilleries. The pagoda roof was introduced around the 1890s as it offered an improved air draught, fanning the peat furnace to core temperatures which can reach between 800 and 1200 deg C. In most cases, where most distilleries buy in their malt they have mostly lost their function other than a piece of visual identity. The malt is dried and roasted in the peat reek at 60 deg C for two days and is then ready for the next stage
The malt contains much detritus or 'combings', principally rootlets. These are removed and used as cattle food. The malt is then coarsley ground and becomes known as 'malt grist'.
The malt grist is fed into the 'mash tun' where it is combined with a carefully measured quantity of hot water. This completes the conversion of dextrin into maltose and produces a fermentable solution of the malt sugars caled 'wort' or 'worts'. Again, after several washings to draw out the malt, the solid residue or 'draff' is removed and sold as cattle food. The worts are held in a receiver called an 'underback'. This must be cooled to prevent unwanted decomposition of the maltose and to allow yeast to be introduced. The cooled worts are injected with yeast and the fermented in a further tank or tanks called 'washbacks'. Thirty-six hours or thereabouts of sometimes violent fermentation produces a weakly alcoholic (10 degrees or thereabouts) clear liquid called 'wash', which will now be distilled
Distillation takes place in pear-shaped copper vessels called 'pot stills'. and at least two are required of different types. The wash is first distilled in the 'wash still' to produce an impure intermediate product called 'low wines'. This is then fed via the spirit safe into the low wines charger ready for the next stage of distillation. The spirit safe is a heavy glass-fronted and padlocked box in which the emerging distillate may be inspected and directed onwards or back for redistillation as appropriate. When ready, the low wines are discharged into the low wines still and the process repeated. The final product - raw, unmatured whisky passes via the spirit safe to spirit receiver and spirit store, ready for filling into barrels. Early and late distillation fractions ('foreshots' and 'feints') contain impurities so are recycled back for re-distillation with the low wines. The 'safes' used for spirit storage are exactly that. The moment the intermediate product contains alcohol it comes under the control of the Excisemen and the safes are a necessary means of ensuring that the spirits stay where they are supposed to be and are accurately accounted-for.
The horizontal pipe from the top of the still to the worm is called the Lyne Arm. There is a fair variation in the design of these and distilleries will vigorously defend the design of each as contributing something unique to the final product. Further refinements include a bulge at the base of the column (the "Milton Ball") and in particular the Lomond still which has a refluxing coil in the head which enables the still to be 'tuned' to produce a lighter or heavier spirit. Lomond stills have enabled several distilleries to market two distinct malts. A few stills have water cooling of the neck. Each still has a large hatch on the top of the base of the still, the 'man door' for inspection and cleaning. Further up the neck can be seen a small glass porthole which allows inspection of the contents of the still to ensure it does not rise too far up the neck and boil over. Before the advent of the porthole a wooden ball was swung against the neck of the still and the resulting 'ding' used to determine the state within.
Casks are critical to the taste and appearance of the final whisky. The need is for casks wich will impart a characteristic taste to the whisky without dominaing it or imparting a 'woody' flavour. Principally two types of cask are used - Oloroso sherry casks and American oak Bourbon casks. Some distilleries use intact barrels, others remake barrels from selected staves from more than one source. The barrel may be charred before use, a process which apparently assists the release of vanillin from the wood. No two casks are the same - one may produce a fine whisky and may be refilled and used again whereas its neighbour may taste woody after one filling.
The whisky is left a minimum of three years but usually between 8 and 25 years in wooden barrels to mature. The bonded warehouses are cool and earth-floored to provide an even temperature and humidity. The barrels lose about 2% alcohol per annum - the so-called 'angel's share'. It is worth noting the investment tied up in each one of these modest low stone warehouses - each full-size cask can contain up to 110 gallons - easily &163;15-20,000 of spirit once it reaches the shops.
Occasionally bottlings are produced from one single cask - the so-called 'single single' malts. More normally, several casks of similar ages from the one distillery will be 'married' by vatting them together then maturing them further for a few months.information source: The Edinburgh Malt Whisky Tour