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Whisky Production from A to Z

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by Jon-jon Bauyon

 

Introduction

Whisky or Whiskey is an alcoholic beverage made from grain mash fermentation and distillation. Various grains (malted or un-malted) such as barley, rye, wheat or corn are use to produce different types of whisky. It is then aged in a wooden cask, whether it is produce in Scotland, Japan or USA, they share the same production method. With this article, we will focus on Single Malt Whisky. Let's find out more on how a simple grain becomes the "Water of Life" to many. 

The Beginning

Barley and water have been the basic ingredients to Single Malt whisky production for over 500 years now. It all starts with selecting good quality barley for good quality whisky. 


Laphroaig Distillery's Malting Floor

Malting

Alcohol is produce by fermenting sugar. Barley contains primarily starch. In order to release the sugar, the starch must be split into sugars which is maltose and malt sugar. Traditionally, the barley is steeped in water and left for germination on malting floors. 

Milling

After the conversion of starch into sugar, the malt is dried and coarsely ground which is now called the "grist". 

Kalundborg Vinhus's Mash Tun

Fermentation

The grist is mixed with hot water in the mash tun. If the grist is too coarse, the sugar can't be fully extracted. If the grist is too fine, it sticks together. 

The malt is mashed three times before the sugar solution is cooled in a cooler. In the first run, the water has a temperature of 65 degrees celcius, in the second run, the temperature of the fresh water is increased to 80 degrees celcius. For the final run, the water is heated nearly to the boiling point of 95 degrees celcius. 

The sugar solution must be cooled down to 20 degrees celcius or else, the yeast won't survive in higher temperature. 

The liquid is now called "wort".



Lagavulin Distillery's Wash Back

The wort is now stored for two to four days in the wash backs until fermentation is finished. During the fermentation, the yeast strains convert sugar into alcohol and carbon dioxide. 

The wash backs are covered with leads so no vinegar bacteria can enter and the wash back doesn't boil over. In addition, the wash backs have a rotating blade that continually cuts the foam. The wash back are usually made from Oregon fine or cypress wood, which is specially resistant to fungi. Recently, stainless steel are also use since it doesn't have to be impregnated with chemicals or cleaned so much. 

Fermentation is finished after approximately 48 to 96 hours depending on the distillery. The "beer" (literally) or the "wash" then has an alcohol content of about 8 to 9% and is ready to be filled in the stills. 

Fettercairn Distillery's Wash Still

Distillation 

The wash is filled into the first copper pot still which is called the "wash still" and is heated below and from the inside respectively. Today, mainly hot steam is used for heating. Hot steam is lead through specially shaped heating tubes inside the pot still, thereby heating the "wash". At 78 degrees celcius, the alcohol starts to evaporate before the water does. The alcohol steamed rises in the tapered tube.


Over the neck and the lyne arm, the steam is led into a condenser where the alcohol steam is liquified again. The water is then remains in the pot still .The wash still distills the wash to 20-25% of alcohol. The resulting liquid is now called the "low wines". 


Image from Ardhasaig Distillery

It is then transferred into the second pot still which is called the "spirit still" where they are distilled to 65-70% alcohol content. The third pot still produce a purer alcohol with over 75%. Today, only few distilleries from the lowland region of Scotland uses this, such as Auchentoshan and Bladnoch just to name some.  Keep in mind that the further you distil a whisky, the more it will lose it's individual character. 

During the distillation, the unique shape of the pot stills is the main contributing factor to the taste of a whisky. A long and slim shape produces a soft, pure alcohol like the Glenmorangie, while a short, squat shape produces strong, intense flavours like Lagavulin. The intensity of the heating is also important for the taste. If you heat too strongly, many accompanying substances and fusel oils will get into the whisky, which will surely not be as smooth as if it had been distilled slowly. Typically the distillation process in the spirit still takes up between 4-8 hours. 

Lagavulin Distillery's Spirit Safe

In order to assess the quality low wines and the spirit, the pipes are run through a case usually . made from glass and polished brass, "the spirit and sample safe". The stillman checks the quality and runs spirit back into the still or into the spirit receiver using valves and levers. 

All this is done by visual inspection only and measuring instruments. The stillman cannot taste the spirit. In the sample safe compartment, he can measure the temperature and take samples in order to measure the density of the spirit with hydrometers. The stillman's most important task is to cut off the middle cut properly. As this stage it is decided whether the batch is going to be just good or excellent. The foreshots takes about 30 minutes to run through. The middle cut is then extracted for about 3 hours. The foreshots might contain the highly volatile and poisonous methanol which can lead to blindness or even death if consumed excessively. Modern yeast strains are grown not to produce any methanol at all. That's why the foreshots separation is just a matter of taste today. 

Bowmore Distillery's Spirit Receiver

In small distilleries, the whisky is filled straight from the spirit receiver into the casks. Larger distilleries use an intermediate spirit receiver from which the whisky is then pump into a large collecting tank, the "spirit vat", in which the individual batches are already vatted. This way individual taste differences between separate batches can be levelled out. 

Image from The Whisky Obsession

Maturation

By law, Scotch whisky including blended whisky must mature in a cask for at least 3 years and one day. Single malt is mostly matured 10 or more years. Only oak casks is used since oak wood is breathable and durable. 


The origin of the cask is crucial for the taste of the whisky. Some big distilleries like Glenfiddich mainly use American oak that previously used to mature bourbon whiskey. Whereas Macallan and Bowmore are using European oak like Spanish sherry oak. 


The place where the maturation occurs have a little bit of influence to the taste as well. Old warehouses  are dark and have earth floors and stored in oak beams and stacked on top of each other in 3-6 rows. While modern warehouses have concrete floors so the casks can be moved with forklifts. Hundreds of years ago, the casks were stored lying in the steel racks. Nowadays, the casks are mostly stored upright on pallets. Whisky matures differently depending on the location since there are cold and hot summers, snowy winters, and others have mild climate. 


Usually the whisky is filled into the cask with an alcohol content of 63.5%. The alcohol content decreases 0.2-0.6% annually. It is called the "Angel's share". The fluid level decreases 2% every year. Due to the evaporation and the absorbing of the flavours from the cask, the whisky becomes mellower each year. Samples are taken regularly from each casks to find out when the whisky has reached it's prime. The size of the cask is equally important. Larger cask have a smaller surface proportion to the content and fewer flavours can be extracted from the wood. Therefore, whisky matured in large casks must be stored longer in order to reach the same level of maturation. The opposite happens for a smaller casks. 


In order to achieve a consistent taste, distilleries must blend their single malts accordingly. Most single malt whiskies are blended from several casks. The age statement on the bottle refers to the youngest whisky used for this particular bottle. 

Bottling

Most of the distilleries in Scotland ship their casks to the big bottlers in Glasgow, Edinburgh or Perth. Whereas Glenfiddich , Bruichladdich and Springbank have their own.


The cask bottlings of the independent bottlers such as Gordon & Macphail and others buys newly made malt whisky directly from the distilleries and mature it on their own. They will bottle it straight from the cask and it always a unique whisky. 


The bottles are usually labelled with the name of the distillery, cask type, distillation and bottling date, and sometimes with the cask and bottle number. Single malts taste differently from year to year, similar to wine. Alcohol content can vary greatly. Most of the time, it is between 40-46% and sometimes it is bottled at a natural cask strength. 


Any views or opinions in the post are solely those of the authors and do not necessarily represent the views of the company or contributors.



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