Single malt Scotch
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Single malt Scotch is a type of Scotch whisky, distilled by 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 ethanol derived from grains. (A blend using only single malt whiskies is known as vatted malt.) All single malt Scotch must be produced using a pot still, and be distilled, aged and bottled in Scotland.
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Production
All single malt Scotch goes through a similar batch production process, as outlined below.
Water
One ingredient used in many of the production steps is water. The contribution that the water adds to the whisky is not fully understood, but it appears that soft water that flows through granite before being used is required for superior whisky. Water often adds flavor in other ways: it can pick up flavors and aromas during its trip to the distillery, such as heather and peat from flowing through peat bogs (such as in the case of Talisker). When the Arran Distillery was established in 1995, the location of the distillery was determined by the location of the best source of water.
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 raising 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 content of starch, which is insoluble in water and not available for fermentation by yeast; germinating kernels produce diastase, a family of enzymes that break 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 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 phenols that are released by the peat and absorbed by the malt. The intense, smokey malts from Islay often have phenol levels around 50 parts per million (ppm), 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 mashing process.
Mashing
The malt grist is combined with hot water in a stainless steel basin called a mash tun, which dissolves all the sugar and diastase in the grist. The enzymes then act on the remaining starch, converting more and more of it to maltose, which is dissolved into the water. Typically, each batch of grist is mashed three times or so 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 has an alcohol content of 5 to 7 per cent by volume, and 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, boiling off the ethanol, which has a lower boiling point than water; the vapor is collected in a condenser and liquefied. This spirit, known as the low wines has an alcohol content of about 20 to 40 per cent. 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.
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 its production. When a still wears out and has to be replaced, or when a distillery decides to expand the number of stills it operates, precise measurements 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 they matched those in the old still, and one distiller refuses to allow the cobwebs to be cleaned off his stills for fear of altering the whisky.
Maturation
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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 of single malts are matured for much longer; the general minimum age for a bottled single malt is 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 porous oak; the lost alcohol is poetically known as the angels' share.
Again, the selection of casks has a profound effect on the character of the final whisky. Single malt Scotch is too delicate to be aged in new oak casks, as new oak would overpower the whisky with vanillin and make it overly astringent, 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. Bourbon casks impart a characteristic vanilla flavour to the whisky. An important minority of whisky maturation occurs in sherry casks. This practice arose because sherry used to be shipped to Britain from Spain in the cask rather than having been bottled, and the casks were expensive to return empty and were unwanted by the sherry cellars. Sherry casks are more expensive than bourbon casks, and account for only seven percent of all casks imported for whisky maturation. In addition to imparting the flavours of their former contents, sherry casks lend maturing spirit a heavier body and a deep amber colour. For this reason, single malt Scotches that have been matured in sherry casks are especially prized by blenders, as they give a blend a roundness and richness. Stainless steel shipping containers, however, have reduced the supply of wooden sherry casks, to the extent 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 casks used include those that formerly held port wine and madeira, while experiments with used rum and cognac casks are being performed.
Bottling
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 more cheaply produced grain whisky is used, the result is a blended Scotch whisky. Single malts can be bottled by the distillery that produced them, or as an independent bottling.
The age statement on a bottle of single malt Scotch is the age of the youngest malt included, 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. It should be noted that for whisky, unlike wine, the maturation process does not continue in the bottle.
For a distillery bottling, the whisky to be bottled is generally taken from several casks and mixed in a large vat. The whisky is then diluted, with the same water that was used to mash the malt, to its bottling strength, generally 40 to 46 per cent alcohol, and bottled for sale. Recently, cask-strength, or undiluted, whisky has become popular, with alcohol content as high as 60 per cent.
Independent bottlers, such as Gordon & MacPhail, Signatory, Hart Brothers, and Cadenhead, buy casks of single malts and either bottle them immediately or store them for future use. Many of the independents began as stores and merchants who bought the whisky in bulk and bottled it for individual sales. Many distilleries do not bottle their whisky as a single malt, so independent bottlings are the only way the single malt gets to market. The bottling process is generally the same, but independents generally do not have access to the distillery's water source, so another source is used to dilute the whisky. Additionally, independents are generally less concerned with maintaining a particular style, so more single year and single cask bottlings are produced.
History
Distillation of whisky has been performed in Scotland for centuries. The earliest written record of whisky production in Scotland from malted barley is an entry on the 1494 Exchequer Rolls, which reads "Eight bolls of malt to Friar John Cor, by order of the King, wherewith to make aqua vitae."
In the following centuries, the various governments of Scotland began taxing the production of whisky, to the point that most of the spirit was produced illegally. However, in 1823, Parliament passed an act making commercial distillation much more profitable, while imposing punishments on landowners when unlicensed distilleries were found on their properties. George Smith was the first person to take out a licence for a distillery under the new law, founding the Glenlivet Distillery in 1824.
In the 1830s, Aneas Coffey and Robert Stein independently invented various continuous stills which produced whisky much more efficiently than the traditional pot stills, but with much less flavor. Quickly, merchants began blending the malt whisky with the grain whisky distilled in the continuous stills, making the first blended Scotch whisky. The blended Scotch proved quite successful, less expensive to produce than malt with more flavor and character than grain. The combination allowed the single malt producers to expand their operations as the blended whisky was more popular on the international market. As of 2004, over 90 per cent of the single malt Scotch produced is used to make blended Scotch.
In the 1980s, single malt became more popular outside of Scotland, with large growth in sales to Japan, Hong Kong, Germany, and the United States. The Japanese beverage company Suntory now owns the Auchentoshan Distillery, while other international companies, such as Allied Domecq (United Kingdom), Seagram (Canada), and United Distillers (Ireland), own many more. The largest distiller to remain under Scottish ownership is William Grant & Sons, owned by the Grant family, with headquarters in Motherwell, Scotland.
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:
- Campbeltown Single Malts
- Highland Single Malts
- Islay Single Malts
- Lowland Single Malts
- Orkney Single Malts (generally placed in the Island category)
See also
References
- Gabányi, Stefan; Stockman, Russell (Tr) (1997). Whisk(e)y (first ed.). New York, New York: Abbeville Press. ISBN 0-7892-3080-9
- Harris, James F.; Waymack, Mark H. (1992). Single-malt whiskies of Scotland. Peru, Illinois: Open Court Publishing Company. ISBN 0-8126-9213-6
- Jackson, Michael; Lucas, Sharon (ed.) (1999). Michael Jackson's complete guide to Single Malt Scotch (fourth ed.). Philadelphia, Pennsylvania: Running Press Book Publishers. ISBN 0-7624-0731-X
- Murray, Jim (2000). The world whiskey guide. London; Carlton Books Limited. ISBN 1-84222-006-3
External links
- The Scotch Malt Whisky Society (http://www.smws.com/archives/archive.html) (single cask malts)sv:single malt