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Single Malt Scotch

Single malt Scotch whisky is Scotch whisky which comes from a single distillery using malted barley as the only grain ingredient. This is in contrast to blended whisky which consists of a mixture of single malt whiskies and whiskies derived from other grains.

Table of contents
1 Production
2 History
3 Regions
4 See also
5 References

Production

All single malt Scotch goes through a similar production process, as outlined below.

Malting

The barley used to make the whisky is malted, or allowed to begin germination, by soaking the grain in water for 2-3 days and then artificially rising their temperature for eight to ten days. Traditionally each distillery had its own malting floor where this was done, but now most of the distilleries use professional maltsters who prepare each distillery's malt to exacting specifications. Malting is used because the barley has a high starch content and germinating kernels produce an enzyme that breaks the starch down into the sugar maltose. The germination is stopped when the optimum enzyme levels have been reached but before much of the sugar has been used for the growing plant. At this stage, the barley is known as green malt.

Kilning and peating

The green malt is then quickly dried in a kiln over a fire. The fire includes an amount of peat which adds a smokey aroma and flavor to the whisky. The smokey flavor comes from phenol that is released by the peat and abosrbed by the malt. The intense, smokey malts from Islay often have phenol levels around 50 parts per million, whereas the much more subtle malts of Speyside have phenol levels of around 2 - 3 ppm. If the distillery uses an outside malting house, the malt is now ready for delivery.

Milling

Most distilleries mill their own malt. The malt is crushed into a powder called malt grist, increasing its surface area, which allows more of the sugar to be extracted during fermentation.

Mashing

The malt grist is combined with hot water in a stainless steel basin called a mashtun, which dissolves all the sugar and starch in the grist. Typically, each batch of grist is mashed three times to extract all the fermentable sugars. The resulting sugary liquid is called wort.

Fermentation

Yeast is combined with the wort in a large vessel (often tens of thousands of litres) called a washback. Washbacks are commonly made of Oregon pine, or stainless steel. The yeast consumes the maltose and gives off carbon dioxide and ethanol. Fermentation can take up to three days to complete. When complete, the liquid is now known as either wash or weak beer.

Distillation

The wash is then pumped into a copper pot still, known as the wash still, to be distilled. The wash is heated and the ethanol, which has a lower boiling point than water, evaporates off and is collected in a condenser and liquified. This spirit, known as the low wines has an alcohol content of about 20 to 40 per cent alcohol by volume. The low wines are then pumped into another pot still, known as the spirit still and distilled a second, and in the Lowlands a third, time. The final spirit has an alcohol content of around 60 to 80 per cent alcohol by volume.

Much of the body, or mouth feel, of the final whisky is believed to come from the size and shape of the stills used in it's production. When a still wears out and has to be replaced, or when a distillery decides to expand the number of stills it operates, exact measurments of the existing stills are taken to ensure the new stills are reproduced exactly like the old. There are stories of master distillers having dents placed in brand new stills so that matched those in the old still, and one distiller refuses to allow the cobwebs from being cleaned off his stills for fear of altering the whisky.

Maturation

The spirit, or unaged whisky, is then placed in wooden barrels or casks for several years to mature. By law, all Scotch must age a minimum of three years in casks, while the vast majority single malts are matured for much longer; the general minimum age for a bottled single malt being eight years. The whisky continues to develop and change as it spends more time in the wood, and ages up to thirty years are not uncommon. Each year spent in the wood reduces the alcohol content of the whisky, as the alcohol evaporates through the pourous oak, which is poeticly known as the angels' share.

Again, the selection of casks has a profound effect on the charactor of the final whisky. Single malt Scotch is too delicate to be aged in new oak casks, as the vanillin in the oak would overpower the whisky, so used casks are needed. The most common source of casks is American whiskey producers, as U.S. laws require that bourbon and Tennessee whiskey be aged in new oak casks. Traditionally, sherry casks were used as sherry was shipped to England in the casks, which were expensive to return empty and unwanted by the sherry cellars. Sherry casks are commonly considered superior to bourbon casks, however, stainless steel shipping containers have reduced their availabilaty, such that the Macallan Distillery builds casks and leases them to the sherry cellars in Spain for a time, then has them shipped back to Scotland. Other caskes used include those that formerly held port wine and madeira, while experiments with used rum and cognac casks are being performed.

Bottling

The whisky to be bottled is generally taken from several casks and mixed in a large vat. However, only whisky made from a single distillery can be used if the whisky is to be called a single malt, if more than one single malt is used the whisky is a vatted malt, and if the cheaper to produce grain whisky is used, the result is a blended scotch whisky. The whisky is then diluted with water to its bottling strength, generally 40 to 46 per cent alcohol by volume, and bottled for sale. Recently, cask strength, or undiluted, whisky has become popular, with alcohol content as high as 60 per cent.

The age statement on a bottle of single malt Scotch is the age of the youngest malt inlcuded, as commonly the whiskies of several years are mixed together to create a more consistent house style. On occasions when a year produces a superior whisky, it is often bottled alone with distilled in and bottled in labels instead of the regular age statement. This is the standard method for the Glenrothes Distillery, whose label is a copy of the hand written cask tasting card, signed by the master distiller when he tasted and approved the cask several times during the maturation process.

History

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Regions

Flavor, aroma, and finish will differ widely from one single malt to the next, but generally the region the malt is from will give you an idea of what to expect in its general character.

Single Malt Scotch whisky can be categorized into the following regions and sub-regions:

See also

Wikipedia:WikiProject Malt Whisky is a form that can be used to review tasting notes.


References