The regulations defining Irish whiskey and its production are rather simple when compared to those of bourbon or Scotch. According to the Irish Whiskey Act of 1980, to be called an Irish whiskey a spirit must be:

• Distilled and aged in the Republic of Ireland or in Northern Ireland
• Distilled to an alcohol by volume level of less than 94.8% from a yeast-fermented mash of cereal grains in such a way that the distillate has an aroma and flavor derived from the materials used
• Aged for at least three years in wooden casks
• Traditionally, the base used in Irish whiskey is barley, but oats, rye, wheat, or even corn may be used.

There are several types of Irish whiskey, including pure pot still, single malt, single grain, and blended.

• Pure pot still whiskey is a blend of both malted and unmalted barley distilled in a pot still. Unmalted barley supplies the spicy freshness that is often associated with Irish whiskey.
• Single malt Irish whiskey is made from 100% malted barley by a single distillery in either column or pot stills.
• Grain Irish whiskey is distilled from one or more of the following: oats, corn, wheat, rye and/or barley. It may be produced in any kind of still, though it is typically distilled in a Continuous Column Still. Most grain whiskies are used in blends.
• Blended Irish whiskey constitutes 90% of all Irish whiskey production and is made from single malt and grain whiskies.

Irish whiskey differs from Scotch in more than just spelling (with the Scots dropping the ‘e’). For example, where Scotch starts with entirely malted barley, Irish whiskey typically starts with a mix of malted and unmalted barley.

Most Irish whiskey is distilled three times while the majority of Scotch whisky is distilled only twice. In addition, the Irish rarely use peat in the malting process, which results in a smoother finish than the smoky, earthy finish of some Scotches. However, while these generalizations are often true, we should point out that there are notable exceptions to these "rules." There are some Irish whiskeys that taste more like Scotch and vice versa.

According to F. Paul Pacult, publisher of The Spirits Journal, Irish whiskey “is solid and well made, and it offers tremendous taste and approachability.” In short, Irish whiskey is distinctive and complex enough for whiskey connoisseurs, yet approachable and gentle enough for those new to the spirit.