How Malt Whisky is Made

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Malt whisky is made from just three ingredients… Barley, Yeast and Water and the method used today is largely the same as a process developed centuries ago.

Malting

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First, barley is steeped in water and spread on a malting floor. These conditions essentially fool the barley into thinking spring has come and it is time to sprout. To do this, barley must access an internal reserve of starch and this is what distillers need to begin to make alcohol. The malting floor is ‘turned’ several times a day to regulate temperature and prevent any build up of mould. After a few days, the barley is transported to a kiln for drying, halting growth in the process and preserving the starch. Drying is achieved by the application of hot air or sometimes by smoking over a peat fire – this is where some whisky gets it’s smokey character.

Mashing


The dried barley is then ground to grist and mashed (mixed with hot water) in a mashtun. This converts starch into sugars which then run off as a syrupy liquid known as ‘wort’.

Fermentation

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The wort is transferred to large vats (or washbacks), made from wood or stainless steel. Yeast is added and left to ferment for a number of days. This process creates a wheat beer of around 9 or 10% alcohol by volume, otherwise known as wash. 

Distillation

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The wash is fed into copper Pot Stills which are then heated. As the temperature rises, the alcohol content evaporates faster than water and rises as vapour. This vapour travels up the neck of the still and along a pipe known as the lyne arm before passing through a condenser to be cooled back into liquid form.

After one distillation the 9% wash has been converted into Low Wines of around 20%. The process is then repeated, this time converting the low wines into a clear spirit known as New Make. The spirit output of a still is divided into three sections – head, heart and tail. Only the heart will be matured while the rest is sent back to be re-distilled with the next batch of wash. 

Maturation

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New Make spirit is put to sleep in Oak casks for a minimum of 3 years – anything less and it can’t be called whisky. It is said that anything up to 60 or even 80% of a whiskies flavour comes from the wood it was matured in. Spirit soaks into the porous oak and draws out both flavour and colour. The casks influence can depend on its size and how many times it has been used before. A new cask will give stronger flavours than an old one for example, and a smaller cask will mature spirit faster than a large one as there is greater contact between the wood and spirit.

The location used to store the cask could also have an effect. Wooden casks breathe, allowing the spirit inside to evaporate (the angel’s share) while also pulling air in at the same time. This is possibly why so many coastal whiskies have a salty, briney note to them.

Blending & Bottling

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The master blender will decide when a cask is ready to be bottled. It could then be bottled as a single cask or it could be vatted with other casks in the warehouse to make a larger batch.

Once the blender is satisfied with their cask selection it’s time to bottle. Few distilleries bottle onsite these days with most transporting to centralised bottling plants. There are a few exceptions however, Springbank for example, take pride in completing the entire process on site.

Then, after all that careful planning and craftsmanship over a number of years the bottle of whisky will finally arrive on shop shelves the world over, waiting patiently for someone like you or me to give it a new home… which is when the fun really begins.

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