What is Irish Whiskey? Definition, Rules, and Types Explained

What Is Irish Whiskey?

Irish Whiskey is a distilled spirit produced and aged on the island of Ireland for at least three years in wooden casks. It is typically made from malted barley and other grains and may be distilled in pot stills or column stills.

Key Requirements for Irish Whiskey

• Must be distilled and matured on the island of Ireland
• Must be aged at least 3 years in wooden casks
• Must be bottled at a minimum of 40% ABV (80 proof)
• Only water and caramel coloring may be added

Have you ever wondered, “Exactly what is Irish Whiskey?” Well, wonder no more. To be designated an Irish Whiskey, certain rules must be followed. In addition, there are a few different varieties of Irish Whiskey, as well as a couple of additional points you’ll need to understand. It gets a little complicated, so buckle up, because here we go!

A Brief History of Irish Whiskey

Irish Whiskey has a long and complex history that stretches back many centuries, although the exact origins of distillation in Ireland remain uncertain. Distillation likely reached Ireland through medieval medical and monastic traditions in continental Europe sometime prior to the 15th century. (Of note, the Technical File states: “Distilling in Ireland probably began in the 6th century when religious monks brought the technique they used to create perfumes and “Eau de Vie” “Water of Life” to Ireland,” although no references for this claim are provided.) These early distillers produced a spirit known in Irish Gaelic as uisce beatha, meaning “water of life,” which eventually evolved into the word whiskey. Written references to whiskey in Ireland appear as early as the 15th century, and by the 16th century distillation had become widespread enough that the English government attempted to regulate it through licensing laws. 

By the 19th century, Irish Whiskey had become one of the most popular spirits in the world, with large distilleries in Dublin exporting whiskey across the British Empire and beyond. However, a combination of events—including trade disputes with Britain, the Irish War of Independence, U.S. Prohibition and growing competition from Scotch whisky—caused a dramatic decline in the industry during the early 20th century. At one point, the number of operating distilleries in Ireland fell to just a handful. In recent decades, however, Irish Whiskey has experienced a remarkable revival, with dozens of new distilleries opening and global demand continuing to grow.

References: Technical File Setting Out The Specifications With Which Irish Whiskey /Uisce Beatha Eireannach / Irish Whisky Must Comply, Difford’s Guide, Diageo Bar Academy, Quench Magazine

The Legal Definition of Irish Whiskey

The U.S. Federal Code Title 27 recognizes Irish Whiskey as per the rules of Ireland. So let’s check the Irish rules out from the Technical File Setting Out The Specifications With Which Irish Whiskey /Uisce Beatha Eireannach / Irish Whisky Must Comply. That document is from the Food Industry Development Division, Department of Agriculture, Food and the Marine, published in October 2014 in Ireland. It is very detailed, and includes the history of Irish Whiskey as well as the specifications and methods for producing it, and each of its variations (types).

Rules From the Technical File

Simplified Version of the Rules of Irish Whiskey

It turns out that the Rules From the Technical File are actually a bit “technical”, so I’ll just explain the gist of them. If that’s good enough for you, you can just skip the official technical section.

• Must be made from malted cereal grains with or without unmalted cereal grains
• The carbohydrates in the grains can be broken down in the mash by the enzymes contained in the malt and/or natural enzymes can be added
• The mash is fermented by yeast
• The fermented grains cannot be distilled to higher than 189.6 proof (94.8 abv)
• After distillation, the distillate must still maintain flavors derived from the original grains – in other words, all of the flavors cannot be distilled out
• The distillate must be aged at least 3 years in new or used wooden casks, not larger than 700 liters in volume
• The only additives after distillation can be water and plain caramel coloring (E150a)
• Must be mashed, distilled and aged in Ireland
• Cannot be exported from Ireland in the wooden casks; if not bottled, it can only be exported in inert containers and proofed down only with demineralized water
• Must be bottled at no less than 80 proof

The Official Technical Version of the Rules of Irish Whiskey

“Irish Whiskey/Uisce Beatha Eireannach/Irish Whisky” is a spirit distilled on the Island of Ireland, including Northern Ireland, from a mash of malted cereals with or without whole grains of other cereals and which has been:

• (a) saccharified by the diastase of malt contained therein, with or without other natural enzymes;
• (b) fermented by the action of yeast;
• (c) distilled at an alcoholic strength of less than 94.8% by volume in such a way that the distillate has an aroma and taste derived from the materials used;
• (d) subject to the maturation of the final distillate for at least three years in wooden casks, such as oak, not exceeding 700 litres capacity. (casks may be new or previously used)
• The distillate, to which only water and plain caramel colouring (E150a) may be added, retains its colour, aroma and taste derived from the production process referred to in points (a) to (d).
• Must be produced in Ireland

In addition, Irish Whiskey cannot be exported in wooden barrels, and like all whiskeys, it must be bottled at no less than 80 proof. Bottling can take place outside of Ireland, however the whiskey must have been transported in inert containers such that no further maturation takes place. Also, when bottling offshore, the water used for proofing down the whiskey must be demineralized, such as not to alter the flavor. It may or may not be chill filtered.

Types of Irish Whiskey Explained (Pot Still, Malt, Grain, and Blended)

So, the general rules of Irish Whiskey are pretty straightforward. Basically, they follow those of whiskey with the specific requirements that it has to age at least 3 years and must be produced in Ireland. However, things get a bit more complicated, because there are 3 distinct Irish Whiskey “varieties“. “Varieties” is the term used in the Technical File, however they are more generally referred to as the “Types of Irish Whiskey”, so we will use that terminology going forward. These types each differ in their composition and production process. The three types of Irish Whiskey (varieties) as defined by the Technical File are Pot Still, Malt and Grain. There’s also a 4th subtype, Blended, which is simply a blend of two or more of the other types. Most people refer to these as the four types of Irish Whiskey, in spite of the Technical File specifically stating that there are three.

Types of Irish Whiskey (Varieties of Irish Whiskey)

• Grain Irish Whiskey or Irish Grain Whiskey is produced from malted barley (not exceeding 30%) and includes whole unmalted cereals, usually maize, wheat or barley, and is distilled on continuous column stills. It is generally triple distilled, but may be double distilled, and usually to 94.5% alcohol by volume
• Pot Still Irish Whiskey or Irish Pot Still Whiskey is a spirit distilled from a mash of a combination of unpeated malted barley, unmalted barley and other unmalted cereals. The mash must contain a minimum of 30% malted barley and a minimum of 30% unmalted barley and be distilled in pot stills. It is typically triple distilled, however double distilled is also acceptable. Large pot stills are usually used.
• Malt Irish Whiskey or Irish Malt Whiskey is a spirit made from a mash of 100% malted barley and distilled in a pot still. The malted barley may be peated or unpeated. It may be double or triple distilled. Smaller pot stills are usually used.
• Blended Irish Whiskey or Irish Blended Whiskey is any combination of 2 or more of the 3 varieties

What Does “Single” Mean?

The word “Single” on a label can be a bit confusing. It simply means that the whiskey is a product of one distillery. Therefore, if the label states “Single Malt Irish Whiskey” it simply means that the entire contents of the bottle were made at one distillery; whiskeys from multiple distilleries cannot be used. It does not mean that only a single type of malt was used.

Does Irish Whiskey Have to Be Triple Distilled?

I don’t know why this “fact” is repeated over and over, but it isn’t true. That is clearly stated in the rules above. Irish Whiskey can be either double or triple distilled. Triple distilled may be more common, but it is not a requirement.

Summary

Well, now you know the answer to the question, “What is Irish Whiskey?”. To sum it up, it follows the general rules of whiskey, with a few additions. First, it has to be distilled and aged in Ireland. Second, it must be aged at least 3 years in wooden casks. Third, it can contain no additives other than water and plain caramel coloring. In addition, there are three variants: Grain, Pot Still and Malt. There is a fourth variant, Blended Irish Whiskey, which is a blend of two or more of the variants. The word “Single” on the label indicates that the whiskey was distilled at a single distillery. And contrary to popular belief, it does not have to be triple distilled. So, there you have it. You now understand Irish Whiskey! Easy peasy! Cheers!☘️🥃

If you would like to learn more, then check out our article Bourbon Whiskey vs Irish Whiskey, where we review the specific differences between these two types of whiskeys. You also may be interested in these Irish Whiskey reviews:

• Northcross Triple Wood Irish Whiskey
• McConnell’s 5 Year Old Irish Whisky
• Two Stacks Single Grain Double Barrel Irish Whiskey
• Drumshanbo Single Pot Still Irish Whiskey
• Muff Irish Whiskey
• Keeper’s Heart Irish + American 110 Proof Whiskey
• Two Stacks The First Cut Signature Blend Irish Whiskey
• Keeper’s Heart 10 Year Single Malt Irish Whiskey
• Fighting 69th Single Malt Irish Whiskey
• Keeper’s Heart Irish + Bourbon

*Some of the bottle shots used in the top of page collage and in the Bushmills Aged 16 Year photo are credited to various distilleries: midletondistillerycollection.com, properwhiskey.com & bushmills.com

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