The Kentucky Question

While Bourbon can legally be made anywhere in the USA, bourbon is strongly associated with Kentucky because we produce 95% of the world's supply! And for good reasons: the distinctive features of our state, including our water, flora and climate, all play specific roles in shaping the flavors and smooth characters of Kentucky bourbons.

A few facts about the Kentucky bourbon industry, courtesy of the Kentucky Distiller's Association:

  • Bourbon is currently a $3 billion industry, generating more than 15,000 jobs

  • Bourbon production has increased more than 170% since 1999

  • In 2014, bourbon production reached its highest level since 1970 with 1.3 million barrels filled - and it was the third straight year with a million or more barrels born

  • In Kentucky there are a million more barrels of bourbon aging than there are people living the state - 5.6 million barrels to only 4.4 million people!

  • The 2014 tax-assessed value of all barrels aging in Kentucky is $1.9 billion - nearly double the value since 2006 ( at merely $1 billion)

  • More than $1.3 billion in bourbon projects is planned, underway or has been completed, including new distilleries, aging warehouses, bottling facilities and tourism centers

… which are all quite impressive numbers

95% of the world’s Bourbon comes from Kentucky.

But this is actually the third golden age of bourbon. Bourbon has had previous heydays in the late 1800s, 1950s & 60s, before today's started back around 2000. And in every bourbon renaissance, Kentucky has been the epicenter.

What Exactly is Bourbon?

Simple question, complex answer.

In brief:

Bourbon is a sub-category of whiskey. (E.g., "bourbon whiskey") Much like you have Irish Whiskey or Canadian Whisky. All bourbon is whiskey but not all whiskey is bourbon

Bourbon is made exclusively from grains and the grains must contain a minimum of 51% corn

The grains are fermented into a product called a 'distiller's beer' then distilled into a liquid alternately called "new spirit," white dog, white lightning, etc

Bourbon "new spirit" cannot exceed 80% alcohol by volume coming off the still

The new spirit must then be cut (reduced in proof) to no more than 62.5% alcohol by volume using nothing but pure water

The spirit is then matured in a virgin oak container (barrel). The barrel must be new and charred (set fire and burned on the inside).

After maturation, bourbon must be bottled at no less than 40% alcohol by volume.

Bourbon cannot have any additives for color or flavor

And (as mentioned) bourbon can only be made in the United States

Bourbon has more rules than any other alcoholic beverage in the world - showing why it's so hard to remember (and explain) exactly what bourbon is!

Veach’s Six Sources of Flavor

Bourbon historian and writer Mike Veach breaks down bourbon into six sources of flavor:

The Grain

The Water





Kentucky lends unique character to bourbon with each of those six sources of flavor.

1. The Grain

Corn is the basis of bourbon (minimum 51%!) and grows well and very plentiful here. To the corn, all bourbon distillers add malted barley which contains enzymes which break down the hard starches in the corn and make it fermentable. Finally a third grain, referred to as a flavoring grain, is added. There are two primary flavoring grains - wheat and rye.

One way of categorizing bourbons is by flavoring grain - either a wheated bourbon or a ryed bourbon. Wheated bourbons tend to be a little bit softer and lighter while ryed bourbons tend to be spicy and more flavorful. Think of the difference between wheat and rye breads for a great example.

The specific ratio of grains makes a recipe called a grain bill or mash bill. Woodford Reserve is a high rye bourbon and they begin their distillery tour by explaining their grain bill - 72% corn, 18% rye and 10% malted barley.

2. The Water

Kentucky sits on a limestone shelf.

From Wikipedia: Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). Most limestone is composed of skeletal fragments of marine organisms such as coral, forams and molluscs.

What used to be an ocean floor is now our signature rolling green hills, thoroughbred pastures, dense forests and rich earth.

3. Fermentation

Alcoholic fermentation is the process of yeast converting sugars into alcohol and other chemical compounds. Straightforward. But the strain of yeast used and length of fermentation create differences in those other compounds in turn creating differences in the final flavor of the alcoholic beverage.

Most major bourbon distilleries use a proprietary yeast strain developed to produce a signature flavor for their products. The specific yeast is so important that Jimmy Russell, master distiller for Wild Turkey, used to keep a backup in his home freezer just as a safety precaution.

Over many decades of acquisitions of other distilleries by Four Roses, master distiller Jim Rutledge collected and maintained five different yeast strains (adorably named V, K, O, Q, and F). By utilizing all five yeast strains and combining the results, Rutledge crafted highly complex and flavorful bourbons. In-the-know bourbon aficionados ask which of the five strains is used for any particular Four Roses single barrel bottling - because they all have their personal favorite strain.,

Fermentation can take as little as 36 hours to up to two weeks. Longer fermentations tend to produce more complexly flavored  'beers,' which eventually become more complexly flavored bourbons.

4. Distillation

The 'beer' for bourbon is more correctly called a 'distiller's beer' since it is destined for distillation.

Distillers produce a dazzling array of differently-flavored bourbons by using:

different types of stills (pot vs. column)

different repetitions of distillation (single, double or triple)

different exit proofs (anywhere below 62.5%)

and different widths of heart cuts

Then, the new spirit is poured into a barrel.

5. Maturation

"Bourbon comes from the barrel"™ is the slogan for Kentucky Knows woodcrafters and aptly so: around 60-80% of the final flavor of bourbon comes from the barrel.

While the liquid is aging inside its barrel, changes in temperature moves the liquid in and out of the virgin, charred oak staves, extracting flavor molecules and oxygenating, plus the char layer inside the barrel filters out some of the harsher components. Summertime heat expands the liquid and drives it into the wood, while the cold of winter contracts it and pulls it back out.

The Kentucky climate has all four seasons every year and pushes each to the extreme. Blazing hot summers and brutally cold winters create the maximum range of expansion and contraction and matures bourbon at a perfect rate. If the climate were hotter, the spirit would evaporate more rapidly and would need to be bottled before fully mellowing. If the climate were cooler, the spirit would take longer to mature and would experience less aggressive oxygenation.

This perfect heat cycling rate still offers a pretty big range for maturation to be ‘complete’ - bourbons hit the bottle at anywhere from three to twenty-three years of barrel time.

At the beginning of maturation, the bourbon rapidly extracts the 'big three' flavors - caramel, vanilla and oak/smoke.  Over time (and we're talking years here), the oxygenation and filtration kick in, resulting in a mellowing of the spirit. So with a younger bourbon, say in the first two to four years, the sweet and smoke flavors will dominate but so will the 'bourbon burn.' Give it a few more years - hitting the six to twelve year range - and the bourbon will soften and develop complexity. Beyond twelve years, the bourbon becomes more delicate but also risks over-extracting from the barrel and incorporating hard wood and ashy flavors.

6. Bottling

Once barrels are deemed mature, they are dumped together to form a batch of bourbon.

The process of sampling barrels, picking them and combining them is typically the job of the master distiller or other highly-trained production personnel. There is an artistry to selecting barrels because each barrel will have a different flavor profile. Combining them to create the same flavor profile batch after batch takes no small skill. Most major bourbons are batched this way.

Or, a bourbon can be allowed to vary from bottle to bottle as a ‘single barrel.’ Blanton’s (“The Original Single Barrel Bourbon Whiskey”) is available exclusively as individual barrel bottlings - no batching at all. So each bottle of Blanton’s will have a slightly different flavor profile from all of the others. That’s why they’re collectables!

The final step is adding water to cut the bourbon from barrel proof to bottle proof. Bourbon raises in alcohol percentage while maturing in the barrel and can end up at anywhere from 55% to up to 70% alcohol by volume - definitely not drinking proof.

Once cut, the bourbon is ready for bottling, shipping to your local liquor store or bar and finally for you to enjoy.


By (1) starting with plenty of corn, (2) topping it off with malted barley and either wheat or rye for flavor, (3) cooking it in mineral-rich limestone water, (4) fermenting it into flavorful distiller's beer, (5) distilling it and (6) pouring it into new, charred oak barrels, (7) leaving the barrels to mature in the highly volatile Kentucky climate and finally (8) selecting and bottling those barrels under the skilled guidance of a bourbon master distiller, Kentucky is able to produce 95% of the world's bourbon whiskey and has claimed the spirit as its own... WHEW!

And now you know "why Kentucky!"