SINGLE MALT FACTS
Single malt Scotch whisky has been produced for centuries. Although Scotch is considered to be an extremely complex and varied drink, it is created using only three simple ingredients, malted barley, yeast and water.
The history, rarity, and uniqueness of single malt Scotch whisky means that human powered malting and the process of creating an inimitable single malt, will always remain as true to its past as possible. It’s a tradition refined over the years by generations of skilled craftsmen so that every ‘dram’ is a small glass of history in its own right.
MALT
The malting process is divided into three stages, steeping, germination, and drying. The desired end result of the malt process is to turn most of the starch in the grain barley into sugar. First the barley is steeped in water. The grain absorbs a certain amount of water and then sprouts. The steeping of the grain timing can be tricky as the grains are steeped only until they begin to sprout. The general rule of thumb is that the barley should take on up to around 46% moisture by weight. The steeped barley is then removed from the water and air rested.
Germination of the barley takes place over 3 to 5 days. During this time, the barley is continually checked and turned to make sure that it is germinating consistently. Speed of germination is controlled by temperature and moisture content.
The final part of the malting process is heat drying the germinated grain. This usually takes place when the barley germ is almost 2/3 of the size of the grain. This heating process stops the grain from germinating any further. The germinated grain is spread over grids in a kiln which is fired from below, and slowly heated with hot air from below. The addition of certain combustible ingredients to the fire will alter the flavour notes of the eventual whisky. The addition of peat to the fire gives the single malt whisky a smokier, peaty flavour. The malt is then ground in a ‘malt mill’ and the husks removed.
MASH
The ground malt mixture is then mixed with hot water in a ‘mash tub’ – the sugar, which will later be turned into alcohol, is released with the addition of hot water and driven to the bottom of the tub. This sugary non-alcoholic liquid is commonly known as ‘wort’.
FERMENTATION
The wort is cooled and transferred to a tank called a ‘washback’. Washback tanks are usually wooden. The yeast strain is chosen by the distiller and added to the wort, the fermentation process begins. For the next two days the sugar gradually turns to alcohol. The process is stopped at this point with a very low alcohol strength – generally around 5 -10% ABV. The fermented liquid is known as ‘wash’.
DISTILLATION
The wash is transferred into ‘stills’ and distilled 2 to 3 times. Scottish ’Pot’ stills tend to be used for single malt distillation. The wash is heated and vapourised and the middle of the distillation is removed into a spirit safe by a skilled ‘stillman’. The maximum ABV allowed for Scotch whisky as laid down in The Scotch Whisky Regulations 2009 is 94.8%.
MATURATION
The new spirit is then transferred into a ‘Cask’ to mature. By law, Scotch whisky must mature in oak casks for a minimum period of 3 years. It is during the whisky’s maturation that it takes on the aromas and flavours of the cask. Two types of oak are used in the maturation process, American white oak and European oak.
The flavour and colour of the whisky are predominantly governed by the type of oak used.
The whisky ‘Butt’ cask holds around 500 litres of liquid and is almost always made from European oak originating from Spain and having formerly contained sherry. As the whisky matures in a ‘Butt’ it will assume a much richer and darker colour. The flavour characteristics will be much fruitier, releasing notes of dark fruit, Christmas cake and spices.
The whisky ‘Barrel’ cask holds around 200 litres of liquid. They are made from American white oak. The whisky in these ‘Barrel’ casks usually has tones of vanilla and coconut with a much lighter more yellow or golden colour.
The ‘Puncheon’ cask also holds 500 litres of liquid, they are mainly made from European oak but can also sometimes be made from American oak.
The fourth type of cask is the ‘Hogshead’. They hold 250 litres of liquid and are almost always made from American oak. The ‘Hogshead’ is created from the staves of bourbon ‘Barrels’. The general rule of thumb is that four Barrels make three ‘Hogsheads’. At the current time, most of the casks in the system are ‘Hogsheads’. It is very common that ‘Hogsheads’ used to mature whisky have previously been used to mature other spirits – the ‘Sherry Hogshead’ is the most common type of these previously used ‘Hogshead’ casks.
Older single malt whiskies are kept in the cask to mature for many years with 60 year olds maturing for over two generations.
TYPES OF SCOTCH WHISKY
Scotch whisky is essentially separated into five categories.
Single malt Scotch – is a Scotch whisky produced from water and malted barley at a single distillery by batch distillation in pot stills.
Single grain Scotch whisky – is a Scotch whisky distilled at a single distillery but, in addition to water and malted barley, the recipe may involve the use of whole grains of other malted or unmalted cereals.
Blended malt Scotch whisky – is a blend of two or more single malt Scotch whiskies from different distilleries.
Blended grain Scotch whisky – means a blend of two or more single grain Scotch whiskies from different distilleries.
Blended Scotch whisky – means a blend of one or more single malt Scotch whiskies with one or more single grain Scotch whiskies. It is said that some popular brands are blended with forty or so whiskies.
The Scotch Whisky Regulations 2009 – IN SUMMARY
Produced at a distillery in Scotland from water and malted barley to which only whole grains of other cereals may be added all of which have been: processed at that distillery into a mash. Fermented at that distillery only by adding yeast. Distilled at an alcoholic strength by volume of less than 94.8% ABV.
Wholly matured in an excise warehouse in Scotland in oak casks of a capacity not exceeding 700 litres (154 imp gal) for at least three years.
Must retain the colour, aroma, and taste of the raw materials used in, and the method of, its production and maturation.
Containing no added substances, other than water and plain (E150A) caramel colouring.
Comprising a minimum alcoholic strength by volume of 40% ABV.