Ever wondered how malt whisky is produced? What are the ingredients and the processes required to create a fine bottle of malt whisky?
Well, barley malt is the single most important product. Barley is transported to the distilleries in fully loaded 40-ton trucks, excluding distilleries with their own malting. A controller from the distillery will take samples and access the quality of the barley. It is accepted once it meets certain quality criteria such as density, humidity, starch content, germination ability, nitrogen content and purity. Now, armed with bags and bags of barley, we’re ready to produce
Malt whisky following the steps below.
Step 1: Malting
Barley is screened to remove any foreign matter, then it is soaked for two to three days in tanks of water known as steeps.
Afterwards, the barley is spread out on a malting floor and allowed to germinate. This takes up another 8 to 12 days. The malting floors must be aired properly so no fungi or bacteria infest the barley.
Saladin Boxes, malting floor
Germination process refers to when barley secretes the enzyme diastase which makes the starch in the barley soluble, thus preparing it for conversion into sugar. Throughout the germination process, barley must be turned at regular intervals to control the temperature and the rate of germination. It should not be overheated.
Using an industrial drum, a mechanical turner is moved through the layer of barley. There is a consistency in the mixing of the grains and the temperature and humidity are regulated by air condition, the starch can thus turn into malt sugar much more effectively than on malt floor. Nowadays, mating is generally carried out in Saladin boxes or in drum malting; both industrial malting process.
Inside the Drum Malting
For traditional malting, the turning of barley is done by hand using the malt shovel. With time, these workers may suffer from bone deformities also known as ‘monkey shoulder’.
Traditional Malting done by hand
Step 3: Fermentation
After cooling the wort, it is passed into a large vessel. Inside, yeast is added. This is known as fermentation. The living yeast reacts with the sugar in the wort and converts it into crude alcohol. This process takes about 48 hours and produces a liquid known as wash, containing alcohol (malt whisky) of low strength, some fermentable matter, and certain by-product of fermentation.
Step 4: Distillation
Malt whisky is distilled twice (sometimes three times) in large copper Pot Stills.
Copper Pot Stills
The liquid wash is heated to a point at which alcohol becomes vapour. The vapour rises up the still and passed into the cooling plant where it is condensed into liquid state. The cooling plant could be in a form of a coiled cooper tube or worm that is kept in running cold water, or any other type of condenser.
The first distillation separates the alcohol from the fermented liquid and eliminates the residue of the yeast and fermentable matter. This distillate is then passed into another still; a second distillation. Only after the spirit reaches an acceptable standard, it will then be collected in the spirit receiver.
Today, malt is produced in drum malting according to exact specifications of the distillers. In the past, distilleries (and breweries) had malt floors to let their barley germinate into malt using human-powered, old-fashion methods.
Many questioned which is better; traditional malting or industrial malting? Experts mostly agree that old-fashioned, human-powered malting as inferior. This is because their malting is subjected to many relatively unpredictable variables such as weather changes, temperature, air humidity, these delays the process.
Currently, only a few distilleries have their own, small traditional malting. Although, this might be regarded as authentic and natural to the public, and it may very well be that this allows for a unique variation of whisky from a specific batch of barley malts. It will cost the distilleries a lot more than industrially produced malt from specialised large-scale malting.
Malting - Whisky.com. (2017). Whisky.com. Retrieved 3 March 2017, from https://www.whisky.com/information/knowledge/production/details/malting.html
Section 3. (2017). Dcs.ed.ac.uk. Retrieved 3 March 2017, from http://www.dcs.ed.ac.uk/home/jhb/whisky/swa/chap3.html