Irish Whiskey Irish Whiskey is whiskey made in Ireland. Most Irish pot still whiskey is distilled three times. Peat is rarely used in the malting process, so that Irish whiskey has a smoother finish as opposed to the smoky, earthy overtones common to some Scotches, although there are notable exceptions to these rules in both Countries. Irish whiskey was once the most popular spirit in the world, though a long period of decline from the late 19th Century onwards greatly damaged the industry. However, Irish whiskey has seen a great resurgence in popularity since the late twentieth century and has been the fastest growing spirit in the world every year since 1990.