How is it Made? Single Malt Whisky
How is it Made?
Single Malt Scotch Whisky
Three ingredients are needed for making single malt whisky: barley, water and yeast. Other grains and cereals are also used in Scotland. Whiskies made with other grains or cereals can be called Scotch but only barley whisky from a single distillery can be called a single malt. Under a European Union regulation
whisky is defined as 'a distilled product from a mash of grains or cereals'. These days regulations cover the minimum strength at which whisky can be bottled (40%), the minimum maturation period (three years in wooden casks) and even the maximum capacity of the recipient used for maturation!
Step one: Malting and Germination.
It is at this stage that sugars in the grain are developed. These sugars are needed in order to create a sweet liquid (the wort) that will be fermented and eventually distilled. To start, the barley is taken from the fields to the malting floor. There, the grains will be steeped in water, for about two or three days, to trigger the germination process. Left to run its course, germination will give us roots and sprouts that will consume the precious sugars needed to produce whisky. This process has to be interrupted.
Step two: Drying the barley.
In order to interrupt the germination process and retain the sugars, barley has to be dried. Most distilleries these days will use hot air or kilns to achieve this. Traditionally, Peat has been used to dry the barley. Doing this, imparts a characteristic smokey, medicinal flavour to barley, this flavours and aromas survive the distillation process and appear in whisky. Most Islay distilleries and some distilleries in the mainland do this. The usage of peat is what gives smoky and peaty whiskies their unique flavour. Some whiskies get smokey flavours from the heavy charring of barrels.
Step three: Extracting the sugar.
Once barley has been dried, it is ground into a 'harsh flour' known as grist. This is done in malt mills. The grist is put into mash tuns, where water is added at different temperatures (each time hotter than the previous time). The resulting liquid is then called wort, the solid residues are known as 'draff' and are used to feed live stock. Highland cows love it!
Step four: Fermenting the wort.
Each distillery will choose to ferment its wort for different periods of time. Fermentation is done in huge containers known as wash backs. There, yeast is added to the wort where it will feed from the abundant sugars present there. The result is a form of rough barley wine with an alcoholic content of between 7- 8%. Some distilleries will ferment their wort for 24 hours while others will ferment it for as long as 96 hours! The results differ from distillery to distillery according to what they want to achieve.
Step five: Distillation.
Once the wash has been fermented, it is now ready to be distilled. Most Single Malts in Scotland are distilled two times. Very few distilleries distill three times (i.e. Auchentoshan
, Benrinnes, Springbank's Hazelburn
) and even less common are quadruple distillations (i.e. Bruichladdich's Octomore Special Edition
2013). The pot stills are made of copper and the first distillation takes place in a wash still where the resulting liquid (AKA low wines) has an alcoholic volume of between 10 and 20%. Up until this stage, the 'low wines' contain little alcohol and too many impurities. A second distillation is carried out in a pot still which is smaller than the wash still. The shape and size of the pot stills are of great importance when distilling. The character of the newly distilled spirit will depend entirely on these two factors. This is because of the way copper interacts, at the molecular level, with the wash and low wines. Reflux also plays a very important role. Some distilleries (i.e. Ardbeg) emphasize it to add desired flavours and characteristics. Up until this stage, the product from the second distillation is a colour-less liquid. Column stills are not used in the making of single malt whisky. The only other type of still allowed to be used are Lomond Stills.
Step six: Maturation.
This step 'makes' whisky as we know it. The interaction of Oak and spirit is what imparts the character and colour to the clear spirit. In Scotland, no whisky can be called such unless it spends a minimum of three years in Oak casks. No other type of wood is allowed for maturing whisky. Most casks in use nowadays are previously used casks from whiskey distilleries in the USA. Ex-sherry barrels (sherry butts or sherry puncheons) are also used. When the pores of the wood open due to a hike in temperature, the spirit gets inside them. When the temperature drops, the spirit comes out taking with it some of the 'character' from the wood. It is often the case that smaller casks mature whisky at a faster rate than larger casks. This is because a larger surface area interacts a lot more with a comparatively smaller quantity of whisky. This causes whisky to obtain more flavours from the wood over a shorter period of time than larger casks. A great example of whisky matured in smaller casks is Laphroaig's Quarter Cask
release. Other notable examples are Springbank Rundlets and Kilderkins and Longrow Rundlets and Kilderkins.