What makes a Bourbon a Bourbon?

In simple terms, a bourbon is a whiskey made in the USA. However, there are a few rules that distilleries must abide by to be able to be classified as a bourbon. These are:

  • It must be made in the United States. 95% of bourbon is made in the state of Kentucky.
  • Aging must take place in a fresh, charred oak barrel. The Scottish whisky industry makes good use of the abundance of these ex-bourbon barrels, for maturing their Scotch.
  • The grain mixture (mash) must be at least 51% corn. This is because corn grows well in the US, and that’s what early pioneers could easily grow and distil in one season. As this is what was historically used for bourbon, that is what makes a bourbon a bourbon, rather than an American whiskey.
  • The liquid cannot enter the barrel at anything higher than 125 proof (62.5% abv), and must be distilled at no more than 160 proof (80% abv.)
  • Nothing except water can be added. Other whiskies may have colours and flavourings added, although bourbon must be totally unadulterated.

How is Bourbon made?

Firstly a mash bill will be determined, with at least 51% corn. For example, Maker's Mark's mash bill is 70% corn, 16% wheat and 14% malted barley. Distillers mix the grains with water and yeast, and then heat and stir the mixture to combine.

For the fermentation process, the mixture is stored in a vat for one to two weeks, to fully ferment the mixture. More yeast and the sour mash (leftover mash from a previous distillation which reduces the pH to curb the growth of bacteria) are then added the mixture. Next, the liquids are separated (which have become ethanol) from the leftover solids (new sour mash) and distilled within copper pot stills.

Once the liquid reaches between 80 and 125 proof, distillers fill the liquid into a fresh charred oak barrel for as long as they wish. For example, Eagle Rare is always matured for 10 years, though many age for only one or two. Next, the bourbon is decanted, diluted and bottled.

You may have noticed, this process is very similar to how Scotch is made. The differences all come down to the ingredients and casks used. Scotch is often made from 100% malted barley, whereas bourbon must use 51% corn in the mash bill. This grain makes the resulting liquid a lot sweeter.

The rules state that the bourbon must be aged in a fresh charred oak barrel, which infuses the liquid with toasted oak and vanilla-caramel flavour. However, the Scotch whisky industry often benefits from a whole host of different casks, from sherry to bourbon, to impart a range of flavours onto the whisky. Otherwise, the fermentation, distillation and maturation processes are largely the same - apart from the warm Kentucky climate of course!

buffalo trace distillery

How did Bourbon originate?

The name 'bourbon' derives from the French Bourbon dynasty, as Bourbon County, Kentucky, was named after the French Royal family (1579-1792) in an expression of gratitude for their assistance in the USA's war of independence. The nearby principal port in Maysville shipped whiskey barrels marked Old Bourbon across the country. Old Bourbon was the first corn whiskey most people had ever tasted, and so bourbon became the name for any corn-based whiskey.

This whiskey had developed as a natural result of early colonists in the early 17th century, from England, France, Spain, Scotland, The Netherlands and Germany. Distilling was a centuries-old activity in Europe, so it makes sense that they would ship stills over the seas for use in the new world. They found that corn both grew the best, and lent itself well to whiskey-making, in the Americas. Bourbon came about in the 1770's, in which Kentucky was found to be the most fertile land for whiskey making.

When a flood of German and Irish immigrants arrived after 1776, when the USA was formed, they helped further establish an American distilling culture with both their expertise, and thirst for alcoholic beverages from their homeland. Over the course of the 1770 to 1790s, many of the famous names of bourbon had made their mark in Kentucky - Evan Williams, Elijah Craig, Jacob Beam and Robert Samuels to name but a few. Bourbon was recognized in 1964 by the U.S. Congress as a "distinctive product of the United States", and this is when the official rules to classify bourbon were defined.

What types of Bourbon are there?

Kentucky Bourbon

Bourbon made in Kentucky, the home of whiskey - over 90% is made here.

Straight Bourbon

To be labelled a straight bourbon, the liquid must be aged for at least two years.

Bottled-in-bond Bourbon

The Bottled-in-Bond Act of 1897 was passed to ensure a whiskey's quality, but also to provide tax incentives for distillers to produce a higher quality product. To be defined as bottled-in-bond, the bourbon must meet these rules. It must be made by single producer in a single season, aged at least four years in a federally bonded warehouse and be bottled at 50% abv.

Small Batch & Single Barrel Bourbon

These limited bourbons are a new phenomenon, and provide a unique, one-off flavour. Blanton's Original Single Barrel is perhaps the most famous example. They are matured within a single barrel, or a small number of barrels.

Wheated Bourbon

These bourbons lean heavily on wheat in their mash bills. They are famed for their smoothness, as well as their mellow, grassy flavour. Maker's Mark and Pappy Van Winkle are examples of wheated bourbon.

High Rye Bourbon

On the other side of the coin, high rye bourbon is one which has a high percentage of rye in the mash bill. They are known for their boldness, with deeply aromatic flavours of mixed spice and dark fruits. Jim Beam and Four Roses are examples of high rye bourbon.

What is the best selling Bourbon?

Maker's Mark was the best-selling bourbon in the world in 2022, closely followed by Bulleit, Woodford Reserve and Jim Beam.

Wondering where Jack Daniel's is on the list? Well, Jack defines itself as a Tennessee whisky rather than a bourbon. Read our blog on the topic, here.

What are classic Bourbon cocktails?

The first cocktail that comes to mind for many is the humble Old Fashioned, one of the oldest known cocktails! Made with sugar, bitters and orange peel, this simple drink expertly brings out the flavour of bourbon. The classy Manhattan was named after the Manhattan club where it originated in the 1880s. It incorporates bourbon, vermouth, and bitters into a coupe glass, and is garnished with a cherry. A Mint Julep is a summer treat, having originated at the Kentucky Derby horse race. It is equally simple, made by shaking bourbon, mint leaves, and simple syrup, and serving over crushed ice. For colder months, the Hot Toddy combines hot water, honey and lemon juice with bourbon for a winter warmer.

Explore our full range of bourbon, here.