The Art of Irish Whiskey Distilling

Malted barley is a key component of whiskey production. Malted barley is produced by steeping raw barley in warm water for 40-60 hours at a temperature of 12-15 degrees in order to make the barley think it is spring time in its natural life cycle and the barley begins to germinate. Once this process starts the barley is then dried out so it can be stored for use. In Ireland we traditionally dry out the barley with a dry heat from a closed heat source. In other countries open peat fires are used and that is how “Peated” whiskeys are produced.

Milling is the process that grinds up malted and unmalted (if you are making pot still whiskey) grains into a rough flour called a “Grist”. This can be done on a hammer mill or roller mill.

The “Grist” is left steep in warm water for a number of hours to create a thin porridge like liquid. This process helps the conversion of starch in the grain into fermentable sugars. This sugary “wort” liquid is collected and is the base of the whiskey that is going to be produced. The left over grain from this liquid is called “Draff” and is usually used as animal feed.

The wort that has been produced is then put into vessels known as “washbacks” and yeast is added. The yeast then consumes the sugar in the wort. The wort is now referred to as wash and, depending on the process, is about 8-12 percent ABV.

The wash is sent to the first of the pot stills and is heated. As alcohol boils at a lower temperature (78.5 degrees) than water it is the first to vaporise, exiting the pot where it is then cooled, collected and distilled a second and a third time if so desired. Ireland allows for double and triple distillation in whiskey making. At Pearse Lyons Distillery we choose to double distil.
Note: Whiskey is clear like water when it is distilled; the colour of Irish Whiskey is developed through the aging process.

Whiskey usually enters the cask at between 63-70 percent ABV. On average 30-40 percent of the whiskey’s flavour is created at the distillation stage. The other 60-70 percent of the flavour is created in the barrels. How long it has been aged in a barrel and what type of barrel used and what it was previously used for also has an enormous influence on the flavour profile of the end product whiskey.

The types of barrels used vary from reused wine barrels such as Sherry, Port and Madeira which would have been the traditional vessels for Irish Whiskey but in more recent decades the vast majority used are reused Bourbon barrels. While aging in wooden barrels whiskey undergoes six processes that contribute to its final flavour: extraction, evaporation, oxidation, concentration, filtration, and colouration.