What’s The Difference Between Whiskey, Bourbon, Scotch, and Rye?

Brown spirits. I love it, you probably love it, but my wife thinks it “tastes like burning”. Which is fine, more for me. The question today is, since all of these liquors look pretty much the same what makes one a Bourbon and one a Scotch?

Who Defines These Things?

A common set of definitions is important to make sure that you know exactly what you’re getting. Here in the United States, the typical spirit varieties are defined in 27 CFR 5.22, but other countries may have their own specific definitions (for example, “champagne” means very different things in France compared to the United States).

For most of the common types of spirits the definitions are pretty well consistent and agreed upon, but in some cases there’s some funky differences and debates going on behind the scenes.

Whiskey (or “Whisky”)

All of the spirits we’ll talk about today are technically a type of “whiskey.” Think of it like a branch of an evolutionary tree in biology — they all start from the same place, but different characteristics make for different kinds of spirits. Like how a beagle and a greyhound are both dogs, but very different kinds of dogs.

Whiskey is a distilled spirit, meaning it starts life as a fermented mash of sugary and starchy ingredients. In this case the typical whiskey is made from grains including barley, wheat, rye, and corn. The grains are mashed, combined with yeast, and left to ferment until the proper level of alcohol has developed.

Single Malt” whiskey means that 100% of the grain used in the whiskey is malted barley, typically of a single variety, and distilled at a single distillery (not blended from multiple distilleries). American whiskey and other un-specified whiskey can use multiple kinds of grains to make their fermented mash.

Once that’s complete, the slurry is heated in a large pot (usually copper, to counteract some sulfur compounds that develop and make the alcohol taste bad) and then fed into a distillation tower. Here, the vapors coming off the still are cooled and condensed into a purified alcohol.

At this point the alcohol is as white as Christmas snow and pretty tasteless. This is often referred to as “white dog” or “white lightning” whiskey. Some companies market this as “moonshine” but technically that would mean the whiskey was illegally produced. So unless you got your spirits out of the back of a truck from a man with suspiciously few teeth then you’ve probably just got un-aged whiskey.

To give whiskey its distinctive caramel color and improve the flavoring, the alcohol is sealed in casks (usually white oak, but sometimes stainless steel with some wood or other flavoring suspended inside) for a long period of time outside in the elements. This exposure to changes in heat and humidity force the spirit into the wood and extract some of the flavor and color into the liquid.

After some period of time the newly produced whiskey is removed form the barrel, sometimes mixed with water to reduce the potency, and bottled for distribution. Bottles which are not diluted with water before packaging are called “cask strength” because it’s exactly how the alcohol came out of the cask.

A version called “straight whiskey” is a legal distinction codified by congress which requires the use of charred new oak barrels in the aging process, and requires that the whiskey be aged a minimum of two years before being bottled. There’s also some specifics about alcohol content at different stages of the process, but that’s way too technical and boring and this isn’t the Wikipedia article.

Single barrel” whiskey, as the name suggests, means that all of the whiskey in the bottle came from just a single barrel. “Small batch” is a rather worthless distinction because there’s no specific requirements — “small” is a relative word — but it typically indicates that while the whiskey may be a combination of different barrels, all of it was distilled in a single run. “Blended” whiskeys can come from many different barrels and even different distilleries based on the bottler’s preference to create a specific aroma and taste.

Every spirit that’s produced along those guidelines can be called a “whiskey”, and some are happy with that simple designation. There are some delicious whiskeys in the world, but for those looking to ensure they get a very specific taste in their alcohol might want to investigate one of the sub-species of whiskey.

Scotch Whisky

Typically, “scotch” is a whiskey that is produced in Scotland according to a set of guidelines set forth by the Scotch Whisky Association. The main points of those guidelines are that all scotch must be:

  • Made in Scotland, on site at the listed distillery
  • Matured in oak casks for no less than three years
  • Containing no added substances (other than water and caramel coloring)
  • Labeled with an age that represents the youngest drop of alcohol in the bottle

That last part is particularly interesting. For distilleries that produce blended scotch whiskeys, they can use any vintage of distilled spirit they want (such as a little bit of a 50 year old batch for flavoring) but if even a single drop of 3 year old alcohol makes it into the bottle then it must be labeled as a 3 year old scotch.

With a scotch whiskey you’ll typically see lighter flavors than other whiskeys, sometimes even a fruity taste, and most times a hint of peat (a flammable bog byproduct often used as fuel in fires to dry and heat the grains before distillation). The relatively cold and steady climate in Scotland means that it needs that time in the barrel (3 years) to develop the flavors and coloring, otherwise it might just be too bland.

Rye Whiskey

Usually associated with Canada due to its popularity in that country, a “rye” whiskey is defined as having rye make up 51% or more of the grains that went into the initial mash. That’s pretty much it. After that qualifying factor, it’s the wild west.


Contrary to popular belief bourbon doesn’t need to be made in Bourbon County, Kentucky. In fact, my favorite bourbon of the moment is produced just outside Austin, Texas. Any whiskey can be called a “bourbon” if it meets the following criteria:

  • Produced in the United States
  • Made from a mixture of grains that is at least 51% corn
  • Aged in new production charred oak barrels

Surprisingly, there is no aging requirement to be called a “bourbon.” However, the designation “Straight Bourbon” means that the alcohol has been aged in the barrel for a minimum of two years. But there’s a slight twist — if the whiskey has been aged less than four years, the label has to tell you exactly how long it was in the barrel. So if there’s no age statement on a straight whiskey, then it is aged at least four years.

What makes bourbon different from almost every other whiskey is the required use of a charred oak barrel. This produces a darker color and a smokey flavor that isn’t seen in scotch, and the use of corn as the primary basis of the mash means that it has a sweeter flavor to offset that otherwise overpowering taste. In my mind, it’s the perfect balance of boldness and smoothness and my go-to kind of whiskey.

Tennessee Whiskey

The United States has very few appellations of spirits and Tennessee Whiskey is one of them.

In this case, you need to start with a bourbon whiskey produced in the state of Tennessee (so already we know it comes from a grain bill the majority of which was corn). From there the whiskey needs to be filtered using the “Lincoln County Process” which involves filtering the whiskey through charcoal prior to being placed in new charred oak barrels. A minimum of two years later the whiskey emerges as Tennessee Straight Bourbon Whiskey.

Appellation Stacking

The use of a single one of these identifiers doesn’t necessarily exclude the others. So technically, you can have a “Small Batch Straight Bourbon Whiskey.” But some of them are mutually exclusive — a cask strength straight whiskey, for example, isn’t possible because the cask strength alcohol content is beyond the acceptable range of a straight whiskey. Similarly you’ll never see a single malt bourbon, because bourbon needs a majority of corn in the grain bill.

Either way, it’s always the strange edge cases that seem to make the most interesting flavors.

And with that, we conclude today’s lesson. Hopefully, you learned at least one new thing from this. And if not, congratulations on already being an awesome whiskey genius. Either way, go pour yourself a drink.

One comment

  1. The MOST straight-forward explanation EVER. So, Lincoln County Process aside, Bourbon is almost as casual a label as Whiskey. Outstanding read and great update, thank you.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.