The Scotch Whisky production process has changed little in the last two hundred years, Scotch is still produced using traditional methods although modern production and quality control are now used to ensure that the quality of the finished product has never been better. How then is it made?
The ingredients of malt whisky are essentially just barley and water. Barley is a crop that is highly suited to the Scottish climate. In our temperate climate summers are cool with temperatures seldom rising much above 20C. We also have lots of summer rain ensuring conditions that are just right for healthy barley crops. This rain also ensures that we always have a plentiful supply of clear, clean water. The source of the water has a significant effect on the taste of the final product. As you would expect, Loch Lomond whiskies all use water originating from the Loch Lomond water table.
The barley grains are the seeds of the plant and they aresteeped in water until they germinate or sprout. At this stage the germinating barley is spread on the floor of a malting house where it continues to develop over the next week or two. During this period the grains are turned over regularly using a “paddle” to allow air to get at them and encourage even development. The starch in the barley turns to sugar and at the optimum time the germination is stopped by placing the barley in an oven or kiln. Traditionally the heat for this oven was peat fired and it was from here that malt whisk acquired its peaty, smoky taste. Nowadays more conventional forms of heating are used and some distilleries retain the peaty flavours by burning peat and blowing the smoke over the grain during the process.
When the barley is dry it is then milled to produce a floury substance known as “grist”. This grist, which is rich in sugar at this time, is then placed mixed with hot water to create a “mash”. It is then placed in a large metal vessel or container called a “mash tun”. The contents of the mash tun are stirred regularly to encourage the release of the sugars. When this process is complete the resulting liquid, now known as “wort”, is drawn off and transferred to large wooden “washbacks”. The remaining solids are called “draff”, which is commonly used as cattle feed.
The washbacks are like giant wooden pails commonly made from Oregon pine or Cypress
both of which have a high resistance to fungi. It is in these washbacks that
the yeast is added to start the fermentation process during which the sugar in
the wort turns to alcohol. Fermentation is a vigorous process, the solution bubbles
and foams furiously before gradually slowing down as the sugar is converted over
a period of two to four days. At this stage the “wash” smells and
tastes similar to beer. It is still quite weak with an alcohol content of no
more than about 8% or 9%.
OK, we now have our liquid wash, which will ultimately become the finished product. The next step is to distil this down to the required alcohol content. The distillation takes place in copper pot stills which have a distinctive, swan-neck shape. The character of the final product is influenced by the shape of the stills and the length of the neck.
Here at Loch Lomond Distillery we also use our unique rectifying stills, which can be adjusted to replicate different lengths of neck. This allows us to produce malt whiskies of different character from the same stills or combinations of stills. You can see examples of both types of still in the image to the right.
Conventionally there are two stills involved in this process, the wash still and the spirit still. The wash still is used to produce the first distillation, which is called “low wines”. This is then distilled for the second time in the spirit still before being collected as the strong distilled spirit. This spirit is not yet useable. As it is produced the first part,the “foreshot”, is too strong and contains undesirable components. The next part, the “middle cut” is what we are looking for. This is diverted into a receiving tank. The final part of the second distillation, the “feints” is too weak to be used but it is saved to be added to the next batch of low wines so that nothing is wasted. Testing of the spirit as it leaves the pot stills takes place in a “spirit safe” sealed by HM Customs and Excise, (pictured right). No tasting is done at any time and all testing with the hydrometer takes place within this sealed spirit safe.
When the final spirit has been collected in the receiving tank it is ready to go into barrels for the next stage of the process, which is maturation. These oak barrels have often been previously used in the production of American Bourbon whiskey. While Scotch whisky benefits from being stored in barrels that have been previously used the Bourbon industry requires that only new barrels are used for this purpose. The second hand bourbon barrels are therefore purchased by Scotch whisky distillers. Sherry, Rum and Port casks are also used. All of these impart their own, unique characteristics into the final product.
The casks are then moved to a bonded warehouse, the “bonded” referring to the fact that the warehouse is once again controlled by HM Customs and Excise. By law, Scotch whisky must remain “in bond” for at least three years but in practice it is usually much more than this. It cannot in fact be called whisky until these three years have passed. Before this it is just referred to as spirit. During this period about 2% is lost through evaporation each year so that about 25% of the contents of a barrel stored for 12 years will be lost to the “angel’s share”. This along with the cost of storing the product for so long all adds to the cost. When you consider that Vodka and some other drinks are produced and bottled within a few days, (no maturation being required), then you see why whisky, which is similarly priced is such good value.
When the malt whisky has been matured for the required it time can be bottled and labelled but if it is to be used as part of a blended whisky the master blender must make his contribution. The blender is the person who decides what whiskies are to be included in the final blend. Each whisky is “nosed” to determine its characteristics and ensure that the consistency of the specific blend is maintained.
As many as thirty or forty different malt and grain whiskies may be included in the final blend and the blender’s experience is critical in ensuring that your favourite blend retains its consistency over a number of years. It is not possible to just use a “recipe” for this. Whiskies come and go like any other product so as one goes off line another must be selected to replace it. The skilled nose of the blender is the single most important factor in this process. The whisky is then transferred to the bottling plant where it is bottled using modern, highly automated methods.
Note: some of the processes involved in the making of Scotch Whisky described above have now been automated. For example during the grain germination process the barley may be turned or “ploughed” with automatic paddles as opposed to manually. The main fermentation and distillation processes however have remained essentially the same in all Scotch whisky distilleries for the last couple of hundred years.