Scotch University

THE MAKING OF MALT WHISKY

The origins of malt whiskey distilling in Scotland are lost in the mists of antiquity. They date back at least to the monks of the 15th century and probably long before.

Although the distillers' art has been understood since earliest times, the subtle aromas and flavours of whiskey have never been fully explained, even today. The ancient term using beatha, which is Gaelic for the Latin aqua vitae or 'water of life', was corrupted in the 18'" century to usky, and then to whisky. The following description is a generalisation of the process.

It should be remembered that each distillery has its own unique specifications.

1. Malting

Best quality barley is first steeped in water and then spread out on malting floors to germinate. It is turned regularly to prevent the build up of heat. Traditionally, this was done by tossing the barley into the air with wooden shovels in a malt barn adjacent to the kiln.

During this process enzymes are activated which convert the starch into sugar when mashing takes place. After 6 to 7 days of germination the barley, now called green malt, goes to the kiln for drying. This halts the germination. The heat is kept below 70°C so that the enzymes are not destroyed. Peat may be added to the fire to impart flavour from the smoke.

2. Mashing

The dried malt is ground into a coarse flour or grist, which is mixed with hot water in the mash tun. The water is added in 3 stages and gets hotter at each stage, starting around 67°C and rising to almost boiling point.

The quality of the pure Scottish water is important. The mash is stirred, helping to convert the starches to sugar. After mashing, the sweet sugary liquid is known as wort. The spent grains - the draff - is processed into cattle feed.

3. Fermentation

The wort is cooled to 20°C and pumped into washbacks, where yeast is added and fermentation begins. The living yeast feeds on the sugars, producing alcohol and small quantities of other compounds known as congeners, which contribute to the flavour of the whisky. Carbon dioxide is also produced and the wash froths violently. Revolving switchers cut the head to prevent it overflowing. After about 2 days the fermentation dies down and the wash contains 6-8% alcohol by volume.

4. Pot Stills

In some mysterious way the shape of the pot still affects the character of the individual malt whisky, and each distillery keeps its stills exactly the same over the years.

In distillation, the still is heated to just below the boiling point of water , the alcohol and other compounds vaporize and pass over the neck of the still into either a condenser or a worm - a large copper coil immersed in cold running water where the vapour is condensed into a liquid.

5. Distillation

The wash is distilled twice - first in the wash still, to separate the alcohol from the water, yeast and residue called pot ale - the solids of which are also saved for use in animal feeds.

The distillate from the wash still, known as low wines, and containing about 20% alcohol by volume, then goes to the spirit still for the second distillation. The more volatile compounds which distil off first - the foreshots, and the final runnings called feints where more oily compounds are vaporized, are both channelled off to be redistilled when mixed with the low wines in the next batch.

Only the pure centre cut, or heart of the run, which is about 68% alcohol by volume is collected in the spirit receiver.

6. Spirit Safe

All the distillates pass through the spirit safe - whose locks were traditionally controlled by the Customs & Excise. The stillman uses all his years of experience to test and judge the various distillates without being able to come into physical contact with the spirit.

The newly distilled, colourless, fiery spirit reduced to maturing strength, 63% alcohol by volume, is filled into oak casks which may have previously contained Scotch whisky, bourbon or sherry, and the maturation process begins.

THE MAKING OF GRAIN WHISKY

1. Scotch grain whisky is usually made from 10-20% malted barley and then other unmalted cereals such as maize or wheat. The starch in the non-malted cereals is released by pre-cooking and converted into fermentable sugars. The mashing and fermentation processes are similar to those used for malt whisky.

2. The wash is distilled in a continuous or Coffey still, named after its inventor Aeneas Coffey. It has two tall columns - a rectifier and an analyser. Cold wash is pumped in at the top of the rectifier and meets steam. The columns in fact act like a heat exchanger. The alcohol is cooled, condenses and flows away as Scotch grain spirit at about 94% alcohol by volume.

3. The distilled grain spirit is lighter in character and aroma than most malt whiskies and therefore requires rather less time to mature. The bulk of matured grain whisky is used for blending.

THE MATURATION PROCESS

While maturing, the whisky becomes smoother, gains flavour, and draws its golden colour from the cask. A proportion of the higher alcohols turn into esters and other complex compounds which subtly enhance each whisky's distinctive characteristics.

By law all Scotch whisky must be matured for at least 3 years, but most single malts lie in the wood for 8, 10, 12, 15 years or longer. Customs & Excise allow for a maximum of 2% of the whisky to evaporate from the cask each year - the Angels' Share. Unlike wine, whisky does not mature further once it is in the bottle.

THE ART OF BLENDING

While the distinctive single malts produced by individual distilleries are becoming increasingly popular, blending creates over 90% of the Scotch whisky enjoyed throughout the world.

By nosing samples in tulip-shaped glasses the blender selects from a wide palate - from the numerous Highland and Speyside malts to the strongly flavoured and peaty Island malts, and the softer and lighter Lowland malts. These malts are combined with grain whiskies - usually 60-80% grain whiskies to 20-40% malt whiskies, and are then left to 'marry' in casks before being bottled as one of the world-renowned blended whiskies.

A blend of a range of malt whiskies, with no grain whisky included, is known as a vatted malt.

The way we make Scotch whisky has evolved over several centuries, but the history of Scotch whisky embraces a much wider heritage; that of Scotland and its people.

What are the main kinds of Scotch Whisky?

There are two kinds of Scotch Whisky - Malt Whisky and Grain Whisky. The Malt Whiskies are divided into four groups according to the geographical location of the distilleries in which they are made, as follows:

(1) Lowland Malt Whiskies, made south of an imaginary line drawn from Dundee in the east to Greenock in the west.

(2) Highland Malt Whiskies, made north of that line.

(3) Speyside Malt Whiskies, from the valley of the River Spey. Although these whiskies come from within the area designated as Highland Malt Whiskies, the concentration of distilleries and the specific climatic conditions produce a whisky of an identifiable character and require a separate classification.

(4) Islay Malt Whiskies, from the island of Islay.

Each group has its own clearly defined characteristics, ranging from the lighter Lowland Malt Whiskies to those distilled on Islay which are generally regarded as the heaviest Malt Whiskies.

Malt Whiskies, which differ considerably in flavour according to the distillery from which they come, have a more pronounced bouquet and flavour than the Grain Whiskies. The production of Grain Whisky is not so influenced by geographical factors and it may be distilled anywhere in Scotland.

What gives Scotch Whisky its distinctive flavour and bouquet?

This is one of the mysteries of the industry and a secret which many imitators of Scotch Whisky have tried in vain to discover. Many theories and explanations have been put forward, but there is no universally accepted solution.

The distilling process itself is one factor. Scotch Whisky, after it has been distilled, contains not only ethyl alcohol and water but certain secondary constituents. The exact nature of these is not fully understood, but it is believed they include some of the essential oils from the malted barley and other cereals and substances that derive from the peat. The amount of these secondary constituents retained in the spirit depends upon the shape of the still and the way it is operated and also on the strength at which the spirit is drawn off. Grain Whisky, because of the process by which it is made, contains fewer secondary constituents than Malt Whisky and is accordingly milder in flavour and aroma.

The natural elements of water, peat and the Scottish climate all certainly have a profound effect on the flavour of Scotch Whisky. Water is probably the most important single factor and a source of good, soft water is essential to a distillery. Peat, which is used in the kiln or oven in which the malt is dried, also has an influence that can be detected in the ‘peaty’ or smoky flavour of many Scotch Whiskies.

The Scottish climate is extremely important, particularly when the whisky is maturing. At this stage the soft air permeates the casks and works on the whisky, eliminating harsher constituents to produce a mellow whisky.

Why do whiskies produced in different distilleries vary in flavour?

This again is a question which it is very difficult to answer with certainty. Most people would agree that the water used is the decisive factor. Adjoining distilleries which draw their water from different sources are known to produce whiskies that are quite dissimilar in flavour.

The size and shape of the stills are also important as are the skill and experience of the men who manage them. It is the objective of the distiller to produce a whisky whose flavour and character remain consistent at all times and in all circumstances. This is the true art of distilling, acquired only after many years and often handed down from one generation to the next.

How many distilleries are there?

There are around 100 Pot Still Malt distilleries and Grain, or Patent Still, distilleries in Scotland; but the number working can vary from year to year.

Can Scotch Whisky be made only in Scotland?

Yes. Many other products which were originally manufactured only in a particular locality have lost their geographical significance and can now be manufactured anywhere. The word ‘Scotch’, however, as applied to whisky, has retained its geographical significance. This is widely recognised in law throughout the world. Thus, whisky may be described as Scotch Whisky only if it has been wholly distilled and matured in Scotland for a minimum of 3 years.

If you could duplicate exactly a Scotch Whisky distillery in, say, Brazil or Spain, could you produce Scotch?

No. For the reason given in the preceding answer, whisky can be called ‘Scotch’ only if it is distilled and matured in Scotland. Whisky produced in Brazil is ‘Brazilian Whisky’ or in Spain ‘Spanish Whisky’. Attempts have been made to copy the unique flavour of Scotch Whiskies in many parts of the world, but with no success whatsoever.

 

Types of Whisky

 

Single Malt Whisky

Single malt whisky is whisky distilled at a single distillery. Malted barley, the only cereal ingredient, and water, is fermented and then distilled using a pot still, batch distillation process. The resultant spirit after distillation is filled into oak casks, which could have originally held bourbon or sherry. To be called Single Malt Scotch Whisky, the spirit must be matured in Scotland for a minimum of 3 years in oak casks, and bottled in Scotland. This type of whisky is the most appreciated amongst whisky drinkers.

Blended Malt Whisky

Blended malt is a combination of Single Malt whiskies, which have been distilled at more than one distillery. This used to be known as vatted or pure malt but following controversy in 2004 the Scotch Whisky Association changed the name to blended malt to disarm confusion. The common misconception about blended malt is that it contains grain whisky this is not the case; blended malt contains 100% malt whisky. Blended grain is similar to blended malt although the whisky used is 100% grain and comes from more than one grain distillery.

Blended Whisky

Blended whisky is a blend of one or more Single Malt whiskies with one or more Single Grain Whiskies. Blended whiskies were created in the mid 19th century to combat the need for a lighter, more palatable spirit as the Highland malt whiskies were of a rather harsh and strong flavour. The boom period in the late 19th century threw up many famous names within the blending industry most notably Tommy Dewar, James Buchanan and Alexander Walker. Blends are less favourable these days as Single Malts are very much the drink of choice, but blends still make up a large part of the whisky drinking market.

Grain Whisky

The invention of the continuous still, firstly patented by Robert Stein then perfected by Aneas Coffey in 1830 revolutionised the distilling industry. At that point in time batch pot still distilling was expensive to run. The costs of raw materials, labour and energy were very high. The Coffey designed continuous still evolved the distilling process in a number of advantageous ways: the cost of resources could be kept down as different unmalted grains such as maize and wheat could be used to make the product and the yield from the distillation gave a higher amount than batch distilling. Grain whisky is of a smoother and lighter flavour than malt whisky as there are less flavour congeners present. The smooth complexion allowed for it to be blended with the harsher flavours of malt whisky to produce a smoother more rounded product. Single grain releases are quite rare although well-aged grain whiskies can hold surprisingly complex flavours.

 

Raw Materials

 Water

The first process in whisky making is finding a plentiful supply of water. Scotland has some of the purest water in the world. Most distilleries are built on good reliable water sources, which can be springs or boreholes. Each unique water source adds to the character and flavour of the whisky.

In areas of the Highlands and especially Islay water will have travelled through peat earth, which gives a brown taint and distinctive flavour to it. This can give a hard quality to the water and many distilleries will use a form of de-ionisation to treat the water. This removes impurities such as mineral salts and leaves a high purity water although many distilleries use hard water as they say it gives a distinct character to their whisky. Water is used in all aspects of production of whisky from malting to mashing and for reducing alcoholic strength. 

Barley

Barley forms the foundation of making whisky. Traditionally, barley was grown on site at the distillery or purchased locally from farmers. Over the years more economically viable ways were developed in the production of barley. Malsters took over the growing and malting process in large-scale processes selling bulk quantities of malt back to the distillers. Distillers have the important job of picking quality barley for production; this plays a big part in the final quality of the whisky.

In 1965 a revolutionary barley was developed called Golden Promise, its hardy, fast maturing and superior malting attributes made it the choice barley for distillers for nearly twenty years. Up until then the class of barley had been rather mediocre. Towards the end of the 20th century new varieties of barley had been bred with all the attributes of Golden Promise but giving higher yields, popular examples are optic and chariot. Barley still continues to be a very important part of whisky.

Yeast To produce ethanol needed for distilling yeast is required. Yeast is an active compound, which is in the Fungi family. Yeast is added to the mash where sugars such as glucose, maltose and maltotriose are present. The yeast through fermentation converts the sugars into ethanol and carbon dioxide. The preferred yeast in the distilling industry is Brewers Yeast. 

 

 

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