|Whisk(e)y, as defined in the US and Europe, is made from grain, yeast and water and matured in oak barrels. The major factors affecting the taste of whisky are the type of grain it is made with, how that grain is processed and the wood the resulting spirit is stored in.|
Scottish malt whisky is made exclusively from malted barley. Malting involves barley being soaked in water to trigger germination, which is halted by heat after 3-5 days. The malted barley is milled and mashed (mixed with water) then fermented with yeast to make a beer like liquid (the wash). This is then distilled, either in batches or by a continuous process, and placed in oak barrels to mature. It is more complicated than this and there are myriad variations on this process beyond the scope of these notes. In this tasting we look at the effect of the grain.
Rather than malted barley, it is possible to make spirit with other grains such as maize (corn), rye, wheat or any mixture thereof. If the resulting mash is distilled to a very high ethanol content (85% ABV or higher), the resulting alcohol is called grain neutral spirit. This retains no flavour of the grain used and is produced very cheaply on an industrial basis. Grain alcohol is also used as a solvent and in a variety of other industrial applications.
However, if you distill at a lower percentage alcohol, the grain or mix of grains can have a major effect on the taste of the resulting whisky. All the flavour of the grain is retained in the extra 15% or so of non-alcohol liquid retained in the new-make spirit and this is one of the major differences between Scottish, American and Irish whiskies.
In Scotland, single malt must be made from just malted barley whereas a grain whisky can be made from any grain. Usually Scottish grain whisky is made from grain neutral spirit and any flavour it has comes from being stored in oak for at least three years. Scottish blended whisky is a mixture of malt whisky and grain whisky, and nearly all grain whisky made in Scotland goes into blends. There are some exceptions, and you can find very old grain whiskies at a fraction of the price for similarly aged malts. Some single grains are very good (for example, Compass Box�s Hedonism), but generally the Scottish are less interested in experimenting with grains than the rest of the world. That is why for this tasting we have chosen three American whiskies and two Irish whiskies.
American whiskey is generally made with a mixture of corn, barley, rye and wheat. The balance of this mixture (the so called mash bill) defines the categorization of the whisky. For example, to be classified a bourbon, the whiskey must be made from 51% corn. Similarly, the mash bill of a rye or wheat whiskey must have a majority of that grain, but need not be exclusive.
In Ireland, the meaning of malt, blend and grain are broadly similar to Scotland. However, the Irish traditionally mix malted and unmalted barley prior to milling and mashing.