Bourbon Brothers Basics - What is bourbon?

If you're anything like me, when you were 18, you thought cans of Jim Beam or Jack Daniel's and cola were pretty much the pinnacle of bourbon. Thankfully, the years have a way of broadening your horizons — and your palate. If you're just starting your bourbon journey, this beginner's guide will help you find your feet.

Pour yourself a glass, and let's talk about the Kentucky Hug — that warm, spreading sensation you get when a good bourbon hits the back of your throat. Not as strange as it sounds, we promise.

Over three posts, we'll cover the basics: the terminology you'll encounter, how to taste bourbon properly, and a few cocktail recipes to impress your mates.

All bourbon is whiskey, but not all whiskey is bourbon.

What Makes a Bourbon?

Whiskey is made by distilling a fermented grain mash — typically a mix of wheat, rye, barley, and corn. Bourbon is a specific, legally defined style of American whiskey. To carry the name, it must meet the following requirements:

• Made in the United States. Around 95% of bourbon is produced in Kentucky, though it can technically be produced anywhere in the USA. Kentucky's unique combination of climate, geography, and pure limestone-filtered water makes it the spiritual home of bourbon. That limestone naturally adds beneficial minerals like calcium while filtering out iron, which can negatively affect flavour.
• At least 51% corn in the mash bill. In practice, it's often much higher. A typical mash bill might be 80% corn, 10% flavouring grain (rye or wheat), and 10% malted barley — though this varies by distillery and expression. The exact grain recipe is called the mash bill.
• Distilled to no more than 80% ABV (160 proof), and must enter the barrel at no more than 62.5% ABV (125 proof).
• Aged in brand new, charred oak barrels. This is perhaps the most defining rule. The charring creates a layer of carbon that filters the spirit and imparts those signature flavours — vanilla, caramel, oak, and spice. Because each barrel can only be used once for bourbon, used barrels are often sold on to Scotch whisky and rum producers.

Bourbon Brothers Glossary

Here are the key terms you'll come across as you explore the world of bourbon:

• Angel's Share / Devil's Cut — As bourbon ages, some liquid is lost to evaporation (the Angel's Share), and some is absorbed into the wood of the barrel (the Devil's Cut). In Kentucky's climate, evaporation alone accounts for roughly 4% loss per year — one reason why older bourbons command a higher price.
• Blended Bourbon Whiskey — A blend of at least 51% straight bourbon with other whiskeys, which may or may not themselves be bourbon.
• Blended Straight Bourbon — A blend made exclusively from straight bourbon whiskeys.
• Bottled-in-Bond — A legal designation established by the Bottled in Bond Act of 1897. The bourbon must be the product of a single distillery, a single distiller, and a single distilling season. It must be aged for at least four years and bottled at exactly 100 proof (50% ABV). Only American spirits can carry this designation.
• Proof — The traditional measure of alcoholic strength, equal to twice the ABV percentage. An 80-proof bourbon is 40% ABV. Distillers typically add water to bring the barrel-strength spirit down to the desired bottling proof, which usually falls between 80 and 100 proof.
• Single Barrel — Bourbon drawn from one individual barrel, rather than blended across multiple barrels. Each bottle from a single barrel release may taste slightly different, reflecting the unique character of that cask.
• Small Batch — Indicates that a limited number of barrels were blended for the release. Note: the term is not legally regulated, so there's no defined minimum or maximum number of barrels — it's largely a marketing descriptor.
• Straight Bourbon — Bourbon aged for a minimum of two years. It may be blended from multiple barrels or mash bills, but must meet all standard bourbon requirements.
• Rickhouse — The warehouse where barrels of maturing whiskey are stored on wooden racks (ricks), stacked several barrels high. The construction materials, ventilation, and a barrel's position within the rickhouse all influence how the spirit develops over time.