Irish Whiskey vs. Bourbon: How Are They Different?

Whiskey (sometimes spelled whisky) is an amber-colored distilled spirit made out of fermented grain (most often rye, wheat, corn, or barley). Most whiskeys are aged in wooden casks before bottling and have a minimum forty percent alcohol by volume (ABV). There are many different whiskey types, usually distinguished by their place of origin, types of grain, blending process, or maturation process.

A spirit must be produced from malt, cereal grain, and barley, then distilled, aged, and bottled in Ireland to qualify as Irish whiskey. Irish whiskey must be aged in wooden casks for a minimum of three years. The more muted, malt character of Irish whiskey shines most when the spirit is aged in less conventional vessels like sherry casks or rum casks. Irish whiskey often undergoes triple distillation to achieve its signature smooth flavor. The spirit is commonly described as warm, spicy, sweet, caramelly, or toasty in flavor.

Irish whiskey is a type of liquor with its own unique blend of ingredients, but there are certain production guidelines that distillers must adhere to in order to classify their whiskey as Irish whiskey. There are four main types of Irish whiskey, which vary in their ingredients and distillation processes.

1. 1. Single malt: Single malt Irish whiskey is made from one-hundred percent malted barley, and is produced at one distillery. It is distilled in a pot still for a malty, sweet flavor.
2. 2. Single grain: Single grain Irish whiskey contains up to thirty percent malted barley, with the addition of other unmalted cereals or whole grains (such as wheat or corn). Single grain Irish whiskey is distilled at a single distillery in a column still.
3. 3. Single pot still: This type of Irish whiskey has a spicy flavor and contains at least thirty percent of malted barley and unmalted barley. It is distilled in a pot still, and made at a single distillery.
4. 4. Blended: Blended Irish whiskey contains any type of grain and can be distilled in pots and/or columns at a single or multiple distilleries. This blended whiskey contains two or more types of Irish whiskeys from different distilleries and has a smooth flavor.

Bourbon is a type of whiskey made from a mixture of fermented grains (typically, corn, barley, and rye). Bourbon falls under the whiskey umbrella, along with Irish whiskey, Canadian whisky, Scotch whiskey, rye whiskey, and corn whiskey. In America, bourbon whiskey has a few legal requirements surrounding the mash bill, barreling, additives, and alcohol content. The mash must contain at least fifty-one percent corn; the spirit must also be aged in newly charred white oak barrels, making for a typically nutty flavor profile and a mellow, caramelized sweetness. The mahogany-colored distilled spirit must also have a minimum of forty percent alcohol by volume (ABV) and cannot contain flavorings or any other additives.

There are a few different types of bourbon, mainly distinguished by the mix of their mash. Here are some of the main varieties of bourbon.

1. 1. Traditional bourbon whiskey: Standard bourbon whiskey contains over seventy percent corn, with the remaining thirty percent made up of a mixture of barley and rye. These bourbons have a slightly sweet and spicy flavor.
2. 2. Rye bourbon whiskey: Rye bourbon whiskey contains a higher concentration of rye than traditional bourbon but less corn and very little barley. This gives the spirit a sharp bite.
3. 3. Wheated bourbon whiskey: Wheat bourbons contain both corn and barley but replace the standard rye with wheat, which gives this beverage a much sweeter flavor than rye bourbon whiskey.
4. 4. Straight bourbon: Straight bourbon must be aged for a minimum of two years in the charred oak barrels, with a label specifying the age if it has matured for less than four years. Straight bourbon lacks additives or colorings.
5. 5. Blended bourbon whiskey: This type of bourbon is a blend that must contain at least fifty-one percent of straight bourbon whiskey that is made from different distilleries.
6. 6. Kentucky bourbon: Kentucky bourbon simply refers to any bourbon made in Kentucky that has been aged for at least one year.

While bourbon is a type of whiskey, there are a few key differences between it and Irish whiskey.

• Flavors: Bourbon tends to be sweeter and denser than Irish whiskey, which is less smokey but very smooth and a bit fruity. Typically, bourbon boasts strong flavors of oak, caramel, marshmallow, and vanilla. Whiskey, however, has a taste that is warm, spicy, sweet, caramelly, or toasty in flavor. The taste varies depending upon the type of bourbon and its distillation process.
• Origin: Bourbon is typically crafted in the United States, while Irish whiskey is only made in Ireland.
• Contents: Irish whiskey mainly uses barley malt with the occasional cereal grains blended in (depending on the type), while bourbon mash typically contains at least fifty-one percent corn.
• Fermentation process: Bourbon must be aged in new charred oak barrels between two and four years, while Irish whiskey is often aged in ex-bourbon barrels or sherry casks for at least three years.
• Uses: While it often is a matter of personal preference, both of these liquors are used for a variety of their own signature whiskey cocktails. For instance, bartenders more commonly use bourbon for the mint julep, the Manhattan, whiskey sour, and the old fashioned, while they turn to Irish whiskey for Irish coffee and Irish sours.

Learn more about mixology from award-winning bartenders Lynnette Marrero and Ryan Chetiyawardana. Refine your palate, explore the world of spirits, and shake up the perfect cocktail for your next gathering with the MasterClass Annual Membership.