How It Is Made: The Production / Manufacturing of Whiskey
How is Scotch Whisky made?
There are two kinds of Scotch Whisky: Malt Whisky which is made by the Pot Still process and Grain Whisky which is made by the Patent Still (or Coffey Still) process. Malt Whisky is made from malted barley only, while Grain Whisky is made from malted barley together with unmalted barley and other cereals.
Malt Whisky
The Pot Still process by which Malt Whisky is made may be divided into four main stages: Malting, Mashing, Fermentation and Distillation.
(a) Malting
The barley is first screened to remove any foreign matter and then soaked for two or three days in tanks of water known as steeps. After this it is spread out on a concrete floor known as the malting floor and allowed to germinate. Germination may take from 8 to 12 days depending on the season of the year, the quality of the barley used and other factors. During germination the barley secretes the enzyme diastase which makes the starch in the barley soluble, thus preparing it for conversion into sugar. Throughout this period the barley must be turned at regular intervals to control the temperature and rate of germination.
At the appropriate moment germination is stopped by drying the malted barley or green malt in the malt kiln. More usually nowadays malting is carried out in Saladin boxes or in drum maltings. in both of which the process is controlled mechanically. Instead of germinating on the distillery floor, the grain is contained in large rectangular boxes (Saladin) or in large cylindrical drums. Temperature is controlled by blowing air at selected temperatures upwards through the germinating grain, which is turned mechanically. A recent development caused by the rapid expansion of the Scotch Whisky Industry is for distilleries to obtain their malt from centralised maltings which supply a number of distilleries, thereby enabling the malting process to be carried out more economically.
(b) Mashing
The dried malt is ground in a mill and the grist, as it is now called. is mixed with hot water in a large circular vessel called a mash tun. The soluble starch is thus converted into a sugary liquid known as wort. This is drawn off from the mash tun and the solids remaining are removed for use as cattle food.
(c) Fermentation
After cooling, the wort is passed into large vessels holding anything from 9,000 to 45,000 litres of liquid where it is fermented by the addition of yeast. The living yeast attacks the sugar in the wort and converts it into crude alcohol. Fermentation takes about 48 hours and produces a liquid known as wash, containing alcohol of low strength, some unfermentable matter and certain by-products of fermentation.
(d) Distillation
Malt Whisky is distilled twice in large copper Pot Stills. The liquid wash is heated to a point at which the alcohol becomes vapour. This rises up the still and is passed into the cooling plant where it is condensed into liquid state.
There are two kinds of Scotch Whisky: Malt Whisky which is made by the Pot Still process and Grain Whisky which is made by the Patent Still (or Coffey Still) process. Malt Whisky is made from malted barley only, while Grain Whisky is made from malted barley together with unmalted barley and other cereals.
Malt Whisky
The Pot Still process by which Malt Whisky is made may be divided into four main stages: Malting, Mashing, Fermentation and Distillation.
(a) Malting
The barley is first screened to remove any foreign matter and then soaked for two or three days in tanks of water known as steeps. After this it is spread out on a concrete floor known as the malting floor and allowed to germinate. Germination may take from 8 to 12 days depending on the season of the year, the quality of the barley used and other factors. During germination the barley secretes the enzyme diastase which makes the starch in the barley soluble, thus preparing it for conversion into sugar. Throughout this period the barley must be turned at regular intervals to control the temperature and rate of germination.
At the appropriate moment germination is stopped by drying the malted barley or green malt in the malt kiln. More usually nowadays malting is carried out in Saladin boxes or in drum maltings. in both of which the process is controlled mechanically. Instead of germinating on the distillery floor, the grain is contained in large rectangular boxes (Saladin) or in large cylindrical drums. Temperature is controlled by blowing air at selected temperatures upwards through the germinating grain, which is turned mechanically. A recent development caused by the rapid expansion of the Scotch Whisky Industry is for distilleries to obtain their malt from centralised maltings which supply a number of distilleries, thereby enabling the malting process to be carried out more economically.
(b) Mashing
The dried malt is ground in a mill and the grist, as it is now called. is mixed with hot water in a large circular vessel called a mash tun. The soluble starch is thus converted into a sugary liquid known as wort. This is drawn off from the mash tun and the solids remaining are removed for use as cattle food.
(c) Fermentation
After cooling, the wort is passed into large vessels holding anything from 9,000 to 45,000 litres of liquid where it is fermented by the addition of yeast. The living yeast attacks the sugar in the wort and converts it into crude alcohol. Fermentation takes about 48 hours and produces a liquid known as wash, containing alcohol of low strength, some unfermentable matter and certain by-products of fermentation.
(d) Distillation
Malt Whisky is distilled twice in large copper Pot Stills. The liquid wash is heated to a point at which the alcohol becomes vapour. This rises up the still and is passed into the cooling plant where it is condensed into liquid state.