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Bourbon Requirements | What Makes Bourbon Not Just Another Whiskey?

Glass of Whiskey in oak barrel

Bourbon is a whiskey – but it is not just any whiskey. This barrel-aged liquor is one of the most common American dark spirits. However, the process of crafting bourbon is unique and requires following strict regulations. In fact, there are several bourbon requirements that distilleries have to meet if they want their whiskey to be considered bourbon.

If you are curious about what makes bourbon, bourbon, let's find out. Here is what sets it apart from other whiskeys in the spirit world.

The Origin of Bourbon

There are many local stories and legends associated with the origin of bourbon; however, there is no proof of their validity. One of the most famous stories that credit the invention of bourbon is of Elijah Craig in 1789. Elijah Craig was a Baptist minister and a distiller in Kentucky who, according to the locals, was the first one to use charred oak casks to create bourbon in 1789. This unique practice is what gives bourbon its lovely warm brown color and its smooth and sweet taste.

On the other hand, the story of distiller Jacob Spears is a local favorite in Bourbon County, but it is rare to hear it outside of the county. As such, these tales might have been fabricated. More plausibly, bourbon may have been a result of the efforts of many distillers who were experimenting with whiskey to make new beverages.

What remains a fact is that corn distilleries existed in the United States way before the late 18th century. Additionally, charring barrels to impart distinctive flavors to the whiskey is a centuries-old practice in Europe.

There are also several old claims that say that Kentucky was the place of origin for bourbon. However, there are no historical facts to support this either. The “Kentucky Bourbon” is produced only in Kentucky, but bourbon itself can be made in any of the 50 states. In fact, all US states craft bourbon, except for Hawaii. What is common among bourbon distilleries in all states is that they meet the strict bourbon requirements. It does not matter in which state it was produced.

The Process of Crafting Bourbon

Bourbon  sour Mash

The process of producing bourbon is similar to the process of crafting other whiskeys. Like other types of liquor, bourbon improves the more time it is stored in a barrel. The barrel imparts caramel and vanilla tones to the whiskey, resulting in the bourbon’s more complex taste and signature dark brown color.

However, distillers cannot age the bourbon indefinitely. Every year, some amount of bourbon leaves the barrel due to evaporation.

If left for enough time, the casks would become empty. In addition, if the bourbon spends too much time in the barrel, it develops a woody and unpalatable taste.

Master distillers frequently check the barrels and are experts in determining when a barrel has matured to perfection without getting undesirable qualities. Unlike other types of aged alcohol, young bourbon is quite enjoyable as well as affordable.

Single-Barrel Bourbon Vs. Small-Batch Bourbon

Glasses of Bourbon Whiskey

For standard bourbon, distilleries pull out several barrels, dump their contents together in a big vat, and mix them until the bourbon matches the flavor profile they are aiming for. Bourbon in every cask tastes slightly different due to the differences in wood and the storage place of the barrel. However, distilleries can blend hundreds of barrels together to get a consistent flavor that matches the whiskey that they typically bottle.

Distillers do not blend single-barrel bourbons. Instead, they select the barrel with the most complex flavors, add water to the bourbon to fix the proof, and then bottle it. As a result, each single-barrel bourbon bottle will have its own unique taste, which may not be replicated. This means higher quality; hence, individuals of discerning tastes often buy more expensive single-barrel bourbon for its distinctive taste profile.

On the other hand, small-batch bourbon is a blend of a small batch of bourbon barrels. The batch can mean anything from two to 200 barrels. All the barrels will still be very carefully selected to offer rich and complex flavors, though they are not as nuanced as single-barrel bourbon. However, this bourbon is still of premium quality. People who appreciate the distinctiveness of taste without having to pay the high price of single-barrel bourbon are prime customers for small-batch bourbon.

If you are interested in reading about some must-try bourbons check out my reviews on Wild Turkey Kentucky Spirit, Blue Run High Rye Bourbon, and Blanton's Gold Edition. For a list of great bourbons under $50 check out my article on Best Bourbon under $50.

Major Bourbon Requirements & Regulations

The United States Code of Federal Regulations has defined the legal bourbon whiskey requirements, which every distillery making bourbon needs to follow. Bourbon has higher regulations than your average whiskey, and the law defines the criteria of what makes bourbon. Let’s take a look at some of the bourbon requirements that need to be met.

Made in the United States

According to the federal regulations code, bourbon is a type of whiskey that is only produced in the United States. Many people believe that for liquor to be bourbon, it needs to be made in the state of Kentucky only. However, this is far from the truth, although about 95 percent of the world’s bourbon supply does come from the Bluegrass State and is Kentucky bourbon.

Most bourbons are made in Kentucky and are Kentucky bourbon since their soil is rich in limestone. As a result, the grain and water in the state have unique minerals and flavors, which lend themselves well to the making of great bourbon.

Despite their close resemblance, Tennessee whiskey, and bourbon whiskey are two distinct liquors. While most of the production methods for both Tennessee whiskey and Bourbon remain similar, one key difference is that bourbon can be made anywhere in the US while Tennessee whiskey must exclusively come from Tennessee. This regional specialty has stood strong since its creation over a century ago-- distilling a flavor all its own throughout America's stately Southland hills.

The Mash

One of the major bourbon requirements is the need for specific types and amounts of ingredients. The mash, which is a mixture of grains for the whiskey, should have at least 51 percent corn. The rest of the grains can be wheat, rye, and malted barley, which impart more nuances to the bourbon. However, there are some bourbons that use only a single type of grain.

Since the mash bill consists of corn, which is a naturally sweet grain, bourbon has a sweeter profile than other whiskeys, like Scotch, which is more sour and bitter.

Barrel Type

Bourbon requirements and regulations mandate that bourbon may only be made inside a specific type of barrel. Distilleries use charred oak barrels to age bourbon. These oak barrels should not have been previously used to make bourbon or other types of liquor. Instead, they need to be completely new. That’s because it is important that the whiskey absorbs as much char from the oak barrels as possible.

This will give a subtle, sweet caramelized taste to the spirit, which is what bourbon is known for. Although the bourbon industry does not have any rules about the type of oak used to make the barrels, most distilleries use white oak since it is the best option for creating a watertight barrel.

Aging Requirements

Distilleries need to age bourbon for at least two years before it can be considered straight bourbon. Two-year-old bourbon will still retain the tastes of the cereal grains from which it is distilled. A higher percentage of corn means a sweeter taste.

Bourbon is also classified as Bottled-In-Bond, and this type of bourbon needs to be aged at least four years. In addition, it must be made in a single distillery during a single season and aged in a federally-bonded warehouse. The hallmark of Bottled-In-Bond bourbon is that it has the smoky flavor of the caramelized wood of the barrel.

Bottled-In-Bond bourbon has a label that identifies the distillery where it was aged and bottled. Often, Americans consider this label as a quality endorsement.

If bourbon has aged for less than four years, distilleries will display a label on the bottle that states how much it has aged. If the bottle consists of a blend of bourbon, then the label must state the age of the youngest bourbon.


The percentage of alcohol content in an alcoholic beverage is its proof level. Distillers write this measurement as double the percentage of alcohol content. For example, if there is 40 percent alcohol in the whiskey, then it is 80 proof.

The bourbon-making process requires strict attention to the proof levels. The maximum proof level for bourbon during distillation should be 160, and during aging should be 125. These restrictions help prevent the higher concentration of alcohol from stripping away the complex flavor nuances in the whiskey.

Finally, the proof of bourbon should be a minimum of 80, which means 40% alcohol content. However, bourbon is readily available in many higher strengths as well.

Additives, Coloring & Flavoring

The only thing that can be put into bourbon is pure water. Add anything else like flavoring or coloring, and it will cease to be bourbon. You can find many different types of flavored whiskeys that started out as bourbon. But if the distillers add anything other than plain water to it, it will technically no longer be bourbon.

Bottom Line

As you can see, there are various bourbon requirements and factors that make whiskey a singular and very prized spirit. Due to the strict standards of making bourbon, distilleries maintain the quality, character, and nuances of the whiskey, which ensures bourbon remains, unlike any other spirit in the market.

If you are interested in reading about some must-try bourbons check out my reviews on Wild Turkey Kentucky Spirit, Blue Run High Rye Bourbon, and Blanton's Gold Edition. For a list of great bourbons under $50 check out my list of Best Bourbon under $50.

Use my exclusive discount code: WHISKEYFOOL10 to receive $10 off qualifying* orders. Copy and paste to use at checkout.

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For all my tastings I use either the Libbey Signature Kentucky Bourbon Trail Whiskey Glass or a traditional Glencairn glass. They both are great for nosing and help in discerning more subtle notes.


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