The methods off making whisky has not really changed over the last years, just three basic ingredients are needed, water, barley and yeast. The only real change is the technology behind the more modern machinery. Most distilleries still use the old methods with little in the way of modern technology. Traditionally there are five stages to the process… malting, mashing, fermentation, distillation and maturation.
Stage 1.. Malting.
The first thing we need to do is the malting process. To begin this process, barley must be germinated and this is called ” malting”. Each distillery has their own preference on the type of barley they use, they want a type that will produce high yields of sugar once fermented. First the barley is soaked for 2-3 days and then spread on the floor of a building (malting house ) It is turned regularly ( traditionally by hand ) to maintain a constant temperature. Once the barley has started to shoot, the germination is stopped by drying it Iver a fire or kiln. Traditionally peat was used to power the kiln but not as often these days, some distilleries still use peat though in order to impart flavour into the malted barley, it is at this point where the type of peat used and length of drying in the thick peat smoke can influence the flavour of the final spirit. The barley is now called ” malted barley” . The next stage is to ground it down in a mill where any husks and other debris are removed. This finely ground malt is now called ” grist”..
The grist is now mixed with hot water. The water is generally from a pure, reliable, local source. The character of this water can have an influence on the final spirit as it can contain minerals from passing over or though granite, peat and other types of rock. This mixture is then put into a large vessel called a mash tun and is then stirred for several hours. Sugars in the malt dissolve and are drawn off through a large seive found at the bottom of the mash tun. This liquid we have is now called ” wart” The process is generally carried out three to four times with the water temperature being increased each time ( between 63 to 95degrees ) . Generally only the wort from the first two is used and the rest is put back into the next batch of new grist. Any unused materials will now be collected and used in the production of feed for local animal feed.
Stage 3.. Fermentation.
The wort is now placed into washbacks and yeast is added. These are traditionally made of oak wood, but now a number of distilleries are starting to insta stainless steel washbacks for s more hygienic and longer life as well as being easier to maintain. Once the yeast is added the fermentation begins, The yeast turns the sugars in the liquid into alcohol.. The fermentation Process can last a few days and the liquid at this stage is called “wash” and is somewhere between 5-10% abv, this is very similar to a beer or ale.
This process can differ in different countries, Traditionally in Scotland double distillation is performed but a handful of distilleries do a tripple distillation. The type of still used in Scotland are generally Pot stills. These stills are made from copper and consist of a bowl shape at the bottom that rises up to the neck at the top, ( similar to a spring onion ) All distilleries have their own shapes but they don’t vary too dramatically . A different shape will give a different flavours to the final spirit, a taller still with a longer neck will give lighter spirit while a shorter, fatter still will produce a fuller richer spirit.
Once the wash enters the wash still it is heated by coal, gas or steam. The liquid is turned into vapours and will now rise up the still until it reaches the neck, where it condenses. This liquid now called “low wines” are passed to the second still, called the spirit still. Once in the spirit still, the process is repeated, then the resulting liquid is split into 3. The alcoholfrom the beginning of the distillation is now called the “heads” are very high in alcohol level and very pungent, these will go back into the next batch of low wines to be used again along with the “tails” these are weak but also pungent. It is only the alcohol from the middle or “heart” of the distillation that is used and this is removed by the stillman. The heart is the spirit that is then watered down to somewhere between 62-65%abv and placed into the casks in order to mature into whisky.
The spirit is has now been placed into the oak casks and stored in a warehouse. The spirit must mature in the cask for a minimum of three years before it is legally allowed to be called whisky. Most casks fall into 3 types, those used to mature Bourbon, which currently can only be used once, Sherry casks and red wine casks, lately though distilleries are experimenting with different types. During the maturation process the whisky will take on flavours and natural oils found in the wood cask and this gives the whisky it’s own characteristic flavour and aroma. Due to the wood being porous, it will breathe in air from the surrounding environment in which it is stored, this will draw the whisky into the wood which is how the flavours and colours enter the whisky. During each year of maturation about 2% of the spirit is lost through evaporation. This is where the term the ” the Angels share” comes into play. The principle here is the older the whisky the more evaporation, less whisky is left in the cask to bottle, the more expensive the whisky due to being more rare.. Of course in warmer climates more water is actually evaporated so the whisky/whiskey that is left can be a higher abv than first placed in the cask.