Whisk(e)y

Whisky is defined as a beverage distilled from a mash of fermented grains, either malted or unmalted. What exactly does that mean though, and why are there so many bottles with the word “Whisky” or “Whiskey” on the label. To convolute it even further, why do some have the ‘e’ and some do not?

There is so much to the world of whiskey, and so much that it can be absolutely overwhelming to even try to understand all of it. What’s great, is that there are ever evolving categories – including the newly created official category of “American Single Malt.” So if you’re like me when I began learning, I had no idea what actually made each category different. Sure, it was pretty clear that Irish Whiskey came from Ireland, Scotch came from Scotland, Japanese Whiskey – well it came from Japan. But what makes individual styles unique? What really is Bourbon, and how does it fit under the whiskey umbrella? How does Colorado make whiskies that follow the rules of whisky making? What is with the ‘e’?

Let’s take a look at a number of the different whiskies from around the world, what rules they have to follow to be classified as each, and get a little information on each one.

Irish Whiskey

Ireland and Scotland both have a claim to the original whiskey distillers. As my family has a lot of Irish heritage, I have selected to place them first on the whiskey list here. Honestly, you don’t have American whiskey as it is today without the influence Irish Immigrants had on it’s creation and evolution.

The Rules for Irish Whiskey

Irish Whiskey must be distilled and aged on the island of Ireland. (Either the Republic of Ireland or Northern Ireland.
It must be distilled from a mash of malted cereal cereal grains that is fermented with yeast.
The spirit must be distilled to no more than 94.8% and distilled in a way that retains the aroma and flavor of the grains.
The whiskey must be aged for a minimum of 3 years in wooden casks that are no larger than 700L.
Be bottled at no less than 40% ABV
Only Water and Caramel Coloring may be added to the product, no other additives are permitted.
If the whiskey is made from two or more such distillates, the product must be referred to as “Blended Irish Whiskey.”

There are also different types of Irish whiskey; Malt, Single Malt, Pot Still, Single Pot Still, Grain, Single Grain, and Blended (as referred to above).

Malt is whiskey made from 100% Malted Barley and distilled in Pot Stills. Single Malt Whiskey is made at only 1 Distillery.

Pot Still Whiskey is distilled from a blend of Malted and Unmalted Barley, each at a minimum of 30%, and no more than 5% of other grains. Single Pot Still Whiskey is made at only 1 Distillery.

Grain Whiskey is made using no more than 30% malted barley, and the rest a mix of unmalted grains such as corn, wheat, or barley, and is distilled in Column Stills. Single Grain Whiskey is made at 1 Distillery.

Blended Irish Whiskey is any mixture of the above styles, and must be labled as blended.

Scotch Whisky (Or just Whisky)

Here in Colorado, A bottle of Scotch is called exactly that, a bottle of Scotch. From what I’ve heard, once you are in Scotland it is just called Whisky. It’s something that I will absolutely keep in mind when I make it out to Scotland eventually.

The Rules for Scotch Whiskey

It must be produced at a distillery in Scotland from water and malted barley, and only whole grains of other cereals may be added.
The barley and other grains all must:
1. Be processed at that distillery into a mash
2. Be converted at the distillery to a fermentable substrate only by endogenous enzyme systems
3. Be fermented at the distillery only by adding yeast
4. Be distilled to an alcoholic strength of less than 94.8% alcohol by volume, or 190 proof.
Must be aged for a minimum of 3 years in oak casks no larger than 700L in an excise warehouse in Scotland
The product must retain the color, aroma, and taste of the raw materials used and method of production and aging.
The whiskey cannot have added substances other that water and plain caramel coloring.
The final product must be at least 40% alcohol by volume.

Scotch has a few subcategories as well, which we will outline below.

Single Malt Scotch Whisky is distilled only from Malted Barley at a single distillery in a pot still.

Single Grain Scotch Whisky is made from a mixture of malted barley as well as other grains such as corn and wheat that is distilled at a single distillery using continuous column stills.

Blended Scotch Whisky is a combination of Single Malt and single grain from different distilleries.

Blended Malt Scotch Whiskey is a blend of single malt whiskies from multiple distilleries, similar to Blended Scotch but only contains Malt whiskies, there is no grain whisky.

Blended Grain Scotch Whisky is a blend of Single Grain Scotch whisky, again similar to the two other blended whiskies above this one only contains non-malt whiskies and is instead only grain whiskies.

Bourbon

Made from predominantly corn, as that is what was widely available, Bourbon is built right into the fabric of America. The distilling process was brought over with Irish and Scottish immigrants who influenced a lot of America’s whiskey making history. The invention of bourbon is often attributed to Elijah Craig, but that can not be confirmed, and the spirit was most likely created by committee – intentional or otherwise. To be called Bourbon, the spirit needs to follow these rules.

The Rules of Bourbon Whiskey

It must be made in the United States of America. (Contrary to what some say, it does not have to be made in Kentucky, although that is the Bourbon center of the U.S.) You will never find any whiskey made outside of the U.S. legally labeled as bourbon.
It must be made from at least 51% corn. There are no restrictions otherwise as to how much rye, wheat, or cereal grains can be added, but they cannot exceed 49%.
It must be distilled at less than 160 proof, or 80% alcohol volume.
The barrels for aging must be new, charred, American White Oak. Each barrel will need to be made from brand new American white oak, and not re-used.
When put into the barrel for aging, the whiskey must not exceed 125 proof, or 62.5% alcohol by volume.
The whiskey must be aged in the new, charred, American White Oak barrels for a minimum of 2 years in order to be designated as Straight Bourbon. There is no maximum time limit for the bourbon to be aged, so it can be as old as the distiller wants.
Finally, the bourbon must have unadulterated flavors. This means that there cannot be anything added to change the flavors, all the flavor must come from the grains, distilling, and aging process.

Bourbon is typically characterized by its sweet flavors from the corn, as well as having influence from the charred oak such as flavors of brown sugar and vanilla. Bourbon does not have sub categories as Scotch or Irish, but there are more American styles we will touch base on below.

Rye Whiskey

American Rye

The mash bill must be made from at least 51% rye. Any of the other 3 grains can be used, but typically American Ryes will use corn and malted barley.
It is distilled to no more than 160 Proof, or 80% Alcohol by Volume.
It must be aged in new, charred oak barrels.
The whiskey must not be put into the barrels at more than 125 proof, or 62.5% alcohol by volume.
To be designated straight rye whiskey, it must be aged for at least 2 years.

Rye whiskey is characterized by it’s spicy, and sometimes fruit flavors, as well as having characteristics from the barrel it’s aged in, similar to bourbon.

Canadian rye does not have any requirements to be labeled as rye whisky, so we will cover that with Canadian Whiskies.

American Single Malt

As of January 19th, 2025, American Single Malt is an official category of American Whiskey. American Single Malt has been on labels for a while now, but this ruling by the TTB is a great culmination of the effort by American Whiskey makers – especially here in Colorado – to recognize the wonderful spirit.

The Rules of American Single Malt

It must be a type of whiskey that is mashed, distilled, and aged in the US.
It is Distilled entirely at 1 US Distillery.
It is distilled from a mash of 100% fermented Malted Barley and to a proof of 160 or less.
Is stored in Oak Barrels (used, uncharred new, or charred new) with a max capacity of 700L.
Is bottled at no less than 80 Proof.
If the Whiskey is aged for 2 years, it may be labeled as “Straight” American Single Malt.

Tennessee Whiskey

Tennessee whiskey is made with the same rules as bourbon, except that it is made in the state of Tennessee. Distillers of Tennessee whiskey producers claim that their whiskey is the only one passed through a charcoal filtering process, and therefore should be differentiated from bourbon. Otherwise, the same rules as bourbon apply.

Tennessee whiskey will have a lot of similar characteristics of bourbon, sweetness from the corn, with the same influences from the aging process. It is also claimed that the charcoal filtering process makes the whiskey smoother, but that is up to you to decide.

American Whiskey

American Whiskey is any whiskey that is made in the United States, but doesn’t conform to one or more of the regulations to be called Rye, Bourbon, or Tennessee whiskey. This can mean it is not aged long enough, has a different mash bill, or anything that disqualifies from being labeled as one of the other styles. That also means that a whiskey labeled as American Whiskey can have a vastly different flavor than another with the same designation.

Colorado Whiskey

This is Mile High Bourbon and Rye after all. Really all Colorado Whiskey means is that it was made in Colorado. It must follow all other labelling laws, so if it is a bourbon-it must be labeled as such.

Canadian Whisky

Canadian Whisky must be mashed and distilled in Canada.
The alcohol content may exceed 90% alcohol by volume, or 180 proof.
The spirits must be aged for a minimum of 3 years in wooden barrels no larger than 700L capacity.
The final whisky must be at least 40% alcohol by volume, or 80 proof.

Whisky in Canada can be labelled as Canadian, Canadian Rye, or Rye, when sold in Canada. However, when exporting the product, usually the labelling must conform to local laws and regulations, so Canadian Rye Whisky sold in the US must conform to US regulations.

Canadian Whisky is usually associated with sweet flavors, easy to drink, and is blended from a selection of whiskies; high proof grain whiskey, lower proof rye grain, Canadian made bourbon style whisky, and sometimes barley whiskey. Flavors also can come from the barrel, similar to bourbon and rye, adding some vanilla and brown sugar notes.

Japanese Whiskey

The only real rule we have found in our research is that it must be produced in Japan.

Japanese whiskey was modeled almost entirely off of the process that Scotch whiskey is made. However, due to the climate differences, and other factors, it will not taste exactly like Scotch. Usually there is more oak influence because the whiskey ages faster with the more extreme climate changes season to season. If you have any more rules or regulations for Japanese whiskey, please let us so we can flesh this one out more.

There are still other styles we didn’t touch on here, including flavored whiskeys, moonshine, and whiskeys from all across other parts of the world. We hope this was a useful guide-and if there is anything you think we should add, please feel free to write us at contactus@milehighbourbon.com.

Cheers!

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