How Single Malt Whisky is made.
Matured min. 3 years
Single Malt Whisky is nothing more and nothing less than 100% barley, water and yeast put together and produced into sugar, so the sugar can turn into alcohol while distilled, and then the evaporated alcohol is contained and the “new make spirit” is made.
But then it can’t call itself whisky just yet.
By Scottish law the produced new make spirit can call itself whisky if they follow these strict rules:
- Is produced from 100% barley (can be different strains of barley)
- All or partly malted barely.
- Mostly fermented under the influence of yeast.
- Been distilled twice for maximum of 94.8%.
- Must be at least 3 years and a day old.
- Matured in wooden cask that contain not more than 700 lites.
- Bottled with a alcohol percentage with a minimal of 40% ABV.
- Only comes from that specific distillery.
Only then after all these regulations the distillery can call its spirit, Single Malt Whisky.
But how is it made then?
I will explain this below.
There would be no whisky without water. That’s why the site of a distillery is often determined by the discovery of a pure source, like a spring or mountain stream. In addition to forming a large portion of the finished product, water is essential to whisky production.
Water encourages the barley to germinate during the malting process and is added at the mashing stage to extract the sugars and make the wort. Distilleries also need cold water to condense the vapours back into a liquid.
Some whiskies also benefit from the addition of a little water in the glass, releasing flavours which might otherwise be masked by notes of peat or brine. The water used in the process must be potable and free from contaminants, high levels of minerals and organic matter. When it comes to production, the distillery needs its water source to be a constant, high-volume supply and – ideally – at a regular temperature for condensing the distilled vapours.
Malting the barley
A distillery will get its barley from a supplier and stores it in a silo.
Since the 70’s malting mostly takes place outside the distillery. There are some distilleries (Highland Park, Balvenie, Bowmore, BenRiach) that produces their own malted barley with long and big malting floors.
Don’t forget that all the barley that’s being mashed and distilled needs to be washed and dried over these floors for them to germinate.
Washing the barley is done in big vates called steeps. This is been done three times, during this process oxygen is added for a period of serval hours. This helps the grain to obsorbe the water more quickly. this can take from one to three days depending on the size of the grain.
when the barley have a water content of around 45% due socking. its layed out on the malting floor and spread evenly.
How to achieve germination?
The wet barley will be spread onto the malting floors to dry. its takes about four to five day for the barley to start germinate.
The diastase-enzyme in the barley will activate and will sprout. This will mean it will be tricked into sprouting and growing.
Back in the days the barley needs to turn over by hand by maltmen with a malt racks or malt shiels.
This so the heat is evenly distributed.
years ago, some mailmen would develop a strain injury known as monkey shoulder. Nowadays they use a machine to turn over the barley.
If the sprouting of the grain is about 1/3 of the grain the process is stopped. The grain as it is now is called green malt.
The Kiln (oven) of the distillery will burn with a temperature between 45 – 75 degrees Celcius. The fuel used in the kiln will depends on the distillery profile or course they are going to go with their whisky.
Will it be peated whisky then peat will be burned.
No peated whisky then coal or gas is used to heat and dry the damp barley.
Temperature is a crucial consideration when drying the grain, to render the enzymes temporarily inactive enabling the grain to be stored safely prior to milling.
The initial phase of kilning essentially dries the surface moisture of the grain, (which means the temperature of the actual grain rises slowly.)
An important stage known as the ‘break point,’ is when the surface moisture has been driven off. After reaching the break point the temperature can gradually be increased to a peak of around 75 degrees centigrade.
However, while a higher temperature means a shorter drying time, the higher the temperature the greater the risk of damaging enzymes.
Kilning also develops the character of the malt.
The malt’s flavour profile essentially develops after the break point, with the original starchy, cereal character yielding a range of sweeter, biscuity, malty notes.
After kilning the barley has a water content of 4 – 5 %.
Peated or not peated whisky?
Like i said before its the choice of the distillery if they want their whisky to taste peated or non peated.
After the malted barley is dried the hole batch is being pushed down below for smashing.
The dried malted barley is ground into a coarse flour or grist,
Then the grist is being mixed with hot water in the mash tun. The temperature in the Pashtun is around 62 – 63 degrees Celsius. The mash is stirred constantly using a rotation rack. Now the sugars are activated and will be in the water.
after 30 minutes of mashing the liquid is drained through the perforated bottom of the mashtun.
The mash is mixed with water a second time but this time the temper will be 70 -75 degrees celsius. after mashing this the liquid is drained off and collected as well.
now the mash is mixed with water for the third time and is heated at a temperate of 80 degrees Celsius.
The content of this mash the sugar contained is lower then the precious mashes so this mash isn’t used for fermentation, but is drained and cooled to 64 degrees celsius and used for the next step in the mashing process.
the sugar liquid is cooled down to 16 -20 degrees celsius. the resulting wort is pumped into the fermentation tank ( so called Washback)
Wash backs and fermentation
inside the wash backs the wort is mixed with yeast. the yeast cells ferment the sugars into alcohol and carbon dioxide. The entire fermentation precise takes up to four days.
The wort has a alcohol content of 8 – 11 % abv. If it reach this amount of alcohol content it can be distilled for the first time.
There are diffrent kinds of wash backs. there are wooden wash back and stainless steel wash backs. some say wooden wash backs will give flavours to the wort others say the amount is to big and the time to short to give off flavors to the wort.
A lavarage wash back is around 12ft across and often 20ft or more deep. distilleries have more then one wash back for their wort to fermeuntate.
The fermentation process will let the liquid inside the wash back rise. Because of the fermentation process the foam in the wash back is constantly growing, that’s why there are fans or steel rotating spinners inside the wash backs. This so the foam won’t overflow the wash back.
The wash is pomp into the first copper still, called the wash still. The copper still will eliminate unwanted sulfur compounds inside the wash.
A cooper still consist of thee parts:
- The kettle (the round shape below)
- The goose arm (line arm)
- The cooler
The size, shape, contact of the copper has an influence of the flavors in the new make spirit.
While distillation the alcohol vapors rise up in the neck of the still to the line arm and slight down into the cooler. This because alcohol evaporate at a lower temperature than water. The water is left in the wash still.
In the shell and tube heat exchanger the alcohol vapors are cooled and condense again. The result is known as low wine. and has an alcohol content of 20 -25 % abv.
the distillation process is now repeated in the copper spirit still. This usually takes around 8 hours. in this step the alcohol and the majority of the flavors and aromatics subsistence is spirited from the water and concentrated. This results into a fine distelant with an alcohol content of 65 – 70 % abv.
The Cut (new make spirit)
This distillate is separated by the distiller in the spirit safe into:
- middle shot
Four shot (also called head):
The four shot contain residue from the previous burning as well as volatile toxic methanol.
Middle shot( also called heart):
the heart it collected and flows through a meter that determines how much spirit tax need to be paid.
The Faints: (also know as the legs)
in the faints fuelsal oils are extracted, because they have a negative effect on the taste and can be harmful.
The fine distill-ant ( also called new make spirit) is pumped into the intermediate spirit receiver.
Each distillery has its own cut point which influences the character of its whisky – as it’s the middle cut of the distillation, known as New Make or the Heart of the run, that goes on to mature in oak casks. The shape, size and number of stills and how the distillate is condensed can have an important influence on the flavour and character of the final spirit, because of the liquid’s contact with the copper. Tall stills or stills with a lye pipe which angles upwards allow greater reflux, giving a lighter spirit. Stills with a smaller surface area or a downwards sloping lye pipe tend to produce a heavier spirit.
The maturation proces
The new make spirit is pumped from the intermediate spirit receiver into the oak casks/ barrels. This process goes by hand and i had the pleasure of filling a barrel at the Benromach distillery.
The new make spirit is partially mixed with spring water and then pumped into the oak casks/ barrel with an alcohol percentage of 67.5% abv.
Now the whisky can sleep in the casks/ barrels. This is where the magic happens. Here it will develop even more flavors, body and aromas.
It all depends on:
- The wood used,
- Roast level of the barrel,
- What was in the barrel before ( wine, rum, sherry, port),
- The amount of time the new make spirit will develop in the cask.
As the casks /barrels breaths in the warehouse, between 1.5 -2 % of the liquid evaporates yearly. This is called the angel share. You can smell this at a distillery warehouse. The walls and ceilings of these warehouses are black due to the evaporations of the whisky.
Do you want to read more about cask maturation ?
The bottling of whisky is often fully automated. The bottles of whisky are placed on a conveyor belt and then filled and labeled. There are still distilleries or independent bottles that do this by hand.
Most whiskies are diluted with water and reduced to 40% – 43% abv.
But there are also cask strength whiskiess. These whiskies go straight from the cask/ barrel into the bottle, with an alcohol percentage of between 53% – 65% abv.
Do you want to read more about cask strength whiskies?
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