Single Malt Whisky
Single malt whisky is whisky distilled at a single distillery. Malted barley, the only cereal ingredient, and water, is fermented and then distilled using a pot still, batch distillation process. The resultant spirit after distillation is filled into oak casks, which could have originally held bourbon or sherry. To be called Single Malt Scotch Whisky, the spirit must be matured in Scotland for a minimum of 3 years in oak casks, and bottled in Scotland. This type of whisky is the most appreciated amongst whisky drinkers.
Blended Malt Whisky
Blended malt is a combination of Single Malt whiskies, which have been distilled at more than one distillery. This used to be known as vatted or pure malt but following controversy in 2004 the Scotch Whisky Association changed the name to blended malt to disarm confusion. The common misconception about blended malt is that it contains grain whisky this is not the case; blended malt contains 100% malt whisky. Blended grain is similar to blended malt although the whisky used is 100% grain and comes from more than one grain distillery.
Blended whisky is a blend of one or more Single Malt whiskies with one or more Single Grain Whiskies. Blended whiskies were created in the mid 19th century to combat the need for a lighter, more palatable spirit as the Highland malt whiskies were of a rather harsh and strong flavour. The boom period in the late 19th century threw up many famous names within the blending industry most notably Tommy Dewar, James Buchanan and Alexander Walker. Blends are less favourable these days as Single Malts are very much the drink of choice, but blends still make up a large part of the whisky drinking market.
The invention of the continuous still, firstly patented by Robert Stein then perfected by Aneas Coffey in 1830 revolutionised the distilling industry. At that point in time batch pot still distilling was expensive to run. The costs of raw materials, labour and energy were very high. The Coffey designed continuous still evolved the distilling process in a number of advantageous ways: the cost of resources could be kept down as different unmalted grains such as maize and wheat could be used to make the product and the yield from the distillation gave a higher amount than batch distilling. Grain whisky is of a smoother and lighter flavour than malt whisky as there are less flavour congeners present. The smooth complexion allowed for it to be blended with the harsher flavours of malt whisky to produce a smoother more rounded product. Single grain releases are quite rare although well-aged grain whiskies can hold surprisingly complex flavours.
The first process in whisky making is finding a plentiful supply of water. Scotland has some of the purest water in the world. Most distilleries are built on good reliable water sources, which can be springs or boreholes. Each unique water source adds to the character and flavour of the whisky.
In areas of the Highlands and especially Islay water will have travelled through peat earth, which gives a brown taint and distinctive flavour to it. This can give a hard quality to the water and many distilleries will use a form of de-ionisation to treat the water. This removes impurities such as mineral salts and leaves a high purity water although many distilleries use hard water as they say it gives a distinct character to their whisky. Water is used in all aspects of production of whisky from malting to mashing and for reducing alcoholic strength.
Barley forms the foundation of making whisky. Traditionally, barley was grown on site at the distillery or purchased locally from farmers. Over the years more economically viable ways were developed in the production of barley. Malsters took over the growing and malting process in large-scale processes selling bulk quantities of malt back to the distillers. Distillers have the important job of picking quality barley for production; this plays a big part in the final quality of the whisky.
In 1965 a revolutionary barley was developed called Golden Promise, its hardy, fast maturing and superior malting attributes made it the choice barley for distillers for nearly twenty years. Up until then the class of barley had been rather mediocre. Towards the end of the 20th century new varieties of barley had been bred with all the attributes of Golden Promise but giving higher yields, popular examples are optic and chariot. Barley still continues to be a very important part of whisky.
To produce ethanol needed for distilling yeast is required. Yeast is an active compound, which is in the Fungi family. Yeast is added to the mash where sugars such as glucose, maltose and maltotriose are present. The yeast through fermentation converts the sugars into ethanol and carbon dioxide. The preferred yeast in the distilling industry is Brewers Yeast.