What is single malt whisky?
Single malt whisky is more than just a drink. It’s a tradition, a culture and an experience. But what exactly makes a whisky a single malt, and how does it differ from other whiskies? Read on, as we reveal all there is to know about single malts.
What is single malt whisk(e)y?
Single malt whisky means that it is produced by a single distillery and made using a single type of malted grain. Typically, this grain is malted barley, although some single malt whiskies are made with rye (usually American single malts). The grain can come from anywhere in the world, but where the whisky is produced determines its origin. The omission or inclusion of the 'e' in whisk(e)y gives a big clue to where that origin is.
What is single malt Scotch whisky?
The terms malt whisky and Scotch whisky are sometimes used interchangeably, however, they aren’t one and the same. While all scotch is whisky, not all whisky is scotch. To qualify as a single malt Scotch whisky, under the Scotch Whisky Regulations, the whisky must meet the following criteria:
- Made exclusively from 100% malted barley, water and yeast.
- Distilled using pot stills at a single distillery.
- Matured for a minimum of 3 years in oak casks.
- Bottled at a minimum strength of 40% abv.
- Distilled below 94.8% abv so that it retains the flavour and aroma derived from its raw materials.
How is single malt whisky made?
While the process of making single malt whisky will be broadly the same for most distillers, we can only tell you how we do things at our own distillery. So here’s how we make each Lagg Single Malt Scotch whisky at our distillery in Lagg, on the Isle of Arran.
Malting
The journey of each Lagg Single Malt Scotch whisky begins with malting. We use 100% Scottish barley - around 94% comes from the east coast of mainland Scotland, and 6% is local barley grown on the island. Once the barley is harvested, it’s then ‘malted’, which allows germination to start. The malted barley is dried in a kiln of burning peat to stop the germination process and create a rich, smoky flavour in the malt.
Mashing
The dried malted barley is then ground into a coarse mixture of flour, grits and husks called grist. The grist is mixed with hot water in our mash tun (imagine a giant teapot) to extract the sugars, creating a sugary liquid known as ‘wort’.
Fermentation
The wort is cooled and transferred to containers called washbacks (we have four, all made of wood) where yeast is added. The yeast ferments the sugars in the wort, producing alcohol and a range of flavourful compounds. After a couple of days, the wash has an alcohol content of about 8% - equivalent to a very strong beer. We have a very cloudy wash as we encourage all the fats and acids to release from the barley, which will give the spirit a heavier, grassier, and earthier flavour.
Distillation
The wash is now distilled twice (the traditional way to do it in Scotland) in our custom-made copper pot stills, a process that separates the alcohol from the water and other impurities. Think of the stills as giant kettles with a heating element in the bottom that we put hot steam through. We have two stills: the first still is the Wash (10,000L) and the second still is the Spirit (6,500L)
The first distillation in the Wash still produces a liquid called the Low Wines, with an alcohol content of roughly 25%. The Low Wines are collected for around 6 hours and then sent to a tank to be distilled for a second time the next day in the Spirit still. The design of the Spirit still helps to generate some of the flavour profiles of the whisky; ours are short and fat with a downward sloping lyne arm (connects the still head to the product condenser) to emphasise the heavily peated whisky we make. The result of the second distillation is a clear spirit known as new make spirit, with an alcohol content of 63.5%.
Maturation
The final part of the process is the longest, where we transfer the new make spirit to oak casks for maturation. This ageing process, which by law must last at least three years in Scotland, imbues the whisky with its distinctive character. Many single malts are aged for much longer than three years, with some whisky varieties maturing for several decades.
The interaction between the spirit and the wood casks contributes to the complexity, colour, and depth of the whisky. We mainly use bourbon casks to showcase the peat of the whisky, but we also experiment with sherry, amarone, cognac, calvados and rum casks.
What gives single malt whiskies their unique taste?
With only a few ingredients involved in the production process, you may wonder how whisky makers differentiate the flavours of their whiskies. There are many ways to do this. The location of the distillery, the source of the water, the type and quality of the barley, the peat used in the smoking process and the shape of the stills; all contribute to the flavour. On top of this, the type of barrels used, as well as the number of years a whisky is aged, can impart very different characteristics.
That’s exactly how we create the unique flavour profiles of our whiskies at Lagg. For instance, our Lagg Single Malt Corriecravie Edition is matured initially in bourbon barrels before being finished for approximately 6 months in Oloroso Sherry Hogsheads which produces flavours of dark chocolate, spiced red berries and hazelnut.
Our Lagg Single Malt Kilmory Edition uses Concerto malted barley, is 100% First-Fill bourbon barrel matured and bottled at 46% ABV, which gives it its initial burst of fruit and smoke on the palate and vanilla, long-lasting finish.
Lagg distillery tour
If you are interested in learning more about how we make our single malt Scotch whiskies, why not visit us for a tour of our distillery, named Distillery of the Year 2023 at the Scottish Whisky Awards. Our expert guides will regale you with the fascinating history of Arran’s distilling past, and you can also sample some of our delicious single malts.