Scotch whisky has been distilled for over 500 years and over that time the process has ben made into an art form.
During this article we will explore how is single malt scotch whisky made and investigate the processes followed to distill and produce that wonderful product that we have come accustom to.
With over one hundred malt whisky distilleries in Scotland there will be differences of how single malt is made as the distillers apply their secret ingredients or process however the main stages are quite consistent, lets take a look at how it all starts.
The quality of any food or beverage product always starts with the quality of the ingredients used, it is therefore imperative that good quality barley, yeast and water is used as the base of whisky. There are as you would expect regulations based around producing and marketing single malt whiskies which includes only using one grain which is barley. Certain types of barley are used and supplied from Scotland and England but also areas within Europe based on the amount of barley required. Fresh spring water is also used to produce single malt whisky.
The barley is steeped in water and left for a few days to germinate on malting floors, the water softens the barley and starts the germination process (starts growing shoots) which in total takes approx. five days. Some distillers produce their own malt while others rely on part supply from modern maltings.
The germination process is then interrupted by spreading the wet barley into the kiln where it is dried with hot air from below until it reaches 4% humidity. This stage is particularly important as the character of the malt really takes shape for example peat can be burnt on the fire and the smoke will then add a smokey peat note. The smoke from the burning gets released through the pagoda roofs that are a common sight at a distillery. The peat that are used in different parts of the Highlands have different characteristics depending on the local vegetation.
After malting the dried barley is milled into powder know as ‘grist’ which must be the correct consistency to extract fermentable sugars for the next stage which is mashing. The milling is carried out in specific machines that sieve out any stones before they enter the machine where they are milled.
The mashing process is carried out in large vats called a mashing tun which uses water to heat up the mash. The hot water induces natural enzymes which help break down the starch inside the malted barley and turns into fermentable sugars.
More hot water is added, and the old water drained off which is repeated up to four times and as each batch runs this draws out more sugar.
The waters from the first wash which is a brown liquid that is known as “wort” and is then passed through as heat exchanger to cool down to temperatures around 34 degrees which is perfect for fermentation. The wort is then pumped back into the fermentation vats. The solids from the left-over grain is high in protein and is often sold to farmers to feed livestock.
The wort then starts a fermentation process whilst in the fermentation vats (also known as *wash backs) which is at the stage where the alcohol is produced as the yeast strains convert the sugar into alcohol and carbon dioxide (CO2) as well as an odorless and colorless gas. The wash backs are covered to contain boiling over, they have a horizontal blade that cuts through the foam. This process continues for approx. 50 – 96 hours.
*A wash back is a large container approx. 12 feet wide by 20plus feet deep.
Distillation means the removal of impurities or the purification of the spirit which is of course ‘alcoholic liquid’.
The wash which is the finished product of fermentation that is distilled for the first time is filled into the first copper pot still called a wash still and is heated from below and inside. Steam is often used for this process running through heating tubes inside the pot still thus heating the wash. The alcohol evaporates before the water and the steam from the alcohol rises into a tapered tube. The steam then carries on its journey until it is liquified again. In producing malt whisky two connect pot stills are used, the first the wash is distilled and has a content of alcohol on average of 22%. This liquid is called “low wines” and is around 22% ABV: which is then transferred into the second pot still to distill to an alcohol percentage to approx. 70%. A third pot still is sometimes used is an alcohol content of approx. 75% is required however the more you distill a whisky the more it will loose its character and taste.
The single malt gets its taste from fats and oils but the most influencing factor is that of the shape of the pot still. The distilling process takes anywhere from 4 – 8 hours after which the operator of the pot stills called the stillman checks the quality visually as well as measures the temperature and decides on the quality of the batch and is categorized as good or excellent.
Filling the casks
The product is then pumped directly into the casks which is a usual process for the smaller distilleries or into a collecting tank before filling the cask. This later has the added benefit of levelling out any differences of taste between the different batches. The barcodes are then added to the outside of the cask for batch identification.
All whiskies in Scotland must mature in an oak cask for a minimum of 3 years and one day however malt whisky is usually matured for a minimum of 10 years but usually 12 years to 21 years. The cask used has a strong influence on the final tastes of the whisky and various distilleries used casks that have been previously used to hold different products such as rum or sherry this then of course has a large bearing on the final taste and gives a brand its own character.
The casks are kept inside and stacked on pallets; the local weather also has a bearing on the finished product. The product is tested through out the process until the master blender decides that the flavor meets that of the expected brand.
After this amazing process and after usually 12 years plus bottling can start, some distilleries have their own botting lines whist others outsource. As the bottles are run down the line the labels are applied as well as the tops firmly put in place and placed into cases and sealed ready for distribution literally world wide so we can all enjoy and savor some of this fantastic product.
One of my favorite distilleries that I have visited is Talisker on the Isle of Sky, and can recommend the distillery tour which is toped off with a ‘wee dram’ to finish, you can’t beat it.
Some personal recommendations of mine, Talisker an island malt from Isle of Skye, Glenbfiddichfrom Speyside and Laphroaig from Islay. Why not order one of the recommendations or choose another fantastic malt and get delivered to your door, click on the images below:
If you have any feedback about single malt scotch whisky that you have tried out or any questions about the ones that I have recommended, please leave your comments below.