Every few weeks someone in the shop asks us whether a whisky glass is "wrong" for bourbon. It isn't. But the question behind the question — what actually separates bourbon from whisky — is worth answering properly, because most explanations either oversimplify it into a slogan ("bourbon is just American whisky") or bury it in production trivia nobody asked for.
Here's the honest version: the difference is legal, not stylistic. Bourbon isn't a flavour profile someone decided on — it's a set of rules written into US federal regulation. Whisky, or whiskey, is the broad category that bourbon sits inside, alongside Scotch, Irish whiskey, rye and Japanese whisky. Once you understand the rules, the flavour differences mostly explain themselves.
Is Bourbon a Type of Whisky?
Yes. Every bourbon is a whisky, but not every whisky is a bourbon — the same way every Golden Retriever is a dog, but not every dog is a Golden Retriever. Whisky is any spirit distilled from fermented grain and matured in wood. Bourbon is one specific expression of that, defined by US law under the Federal Standards of Identity for Distilled Spirits.
To legally carry the name "bourbon," a spirit has to meet a fairly specific checklist:
- Made in the United States (not just Kentucky — that's a strong tradition, not a legal requirement)
- Mash bill of at least 51% corn
- Distilled to no more than 80% ABV (160 US proof)
- Entered into the barrel at no more than 62.5% ABV (125 proof)
- Aged in new, charred oak containers
- No added colouring, flavouring or other spirits
- Bottled at 40% ABV (80 proof) or above
Miss any one of those and it isn't bourbon, regardless of where it's made or how it tastes. There's no minimum age requirement for plain "bourbon" — that only kicks in for "straight bourbon," which must be aged at least two years.
Where Can Bourbon Actually Be Made?
Anywhere in the US — Kentucky just does the vast majority of it, for historical and geological reasons (limestone-filtered water, the right climate for aggressive barrel ageing). Whisky more broadly has almost no geographic restriction: it's made in Scotland, Ireland, Japan, Canada, India, Tasmania and increasingly the Yarra Valley down the road from us. Scotch is the one that shares bourbon's strictness — it has to be made in Scotland, aged at least three years, to earn the name.
What's Actually in the Mash?
This is where most of the flavour argument starts. Bourbon's mash bill is corn-dominant (51% minimum, often 70%+), with wheat or rye and malted barley filling the rest. Scotch single malt is 100% malted barley. Rye whiskey (American) needs at least 51% rye. Irish whiskey is typically a mix of malted and unmalted barley. Japanese whisky largely follows the Scotch template — malted barley, though grain whisky made from corn or wheat is also common in blends.
Corn ferments sweeter than barley. That single fact does a lot of the work in explaining why bourbon tends toward caramel and vanilla, while a barley-forward Scotch tends toward cereal, nuttiness or — depending on the distillery — smoke.
Why Does Bourbon Taste Sweeter Than Scotch?
Two reasons, and the second one surprises people more than the first. The corn mash is one. The other is the barrel: bourbon must go into new, charred oak — a barrel that's never held anything before. New oak gives up its vanillin, caramelised sugars and tannins fast and hard, which is exactly why bourbon can taste rich and sweet even at three or four years old.
Scotch, Irish whiskey and Japanese whisky, by contrast, are matured almost exclusively in used barrels — typically ex-bourbon casks bought from the US once they're legally spent, or ex-sherry casks from Spain. A used barrel has already given up most of its aggressive oak sugars, so it adds flavour more slowly and subtly, which is part of why these styles are usually aged longer to get comparable depth. Neither approach is "better" — they're aiming at different things. If you want the full story on what time in a barrel is actually doing to the spirit, we've written about that separately.
Bourbon vs Whisky vs Scotch vs Rye: A Quick Comparison
| Style | Where it must be made | Mash requirement | Barrel | Minimum age |
|---|---|---|---|---|
| Bourbon | United States | 51%+ corn | New, charred oak | None (2 yrs for "straight") |
| Rye whiskey (American) | United States | 51%+ rye | New, charred oak | None (2 yrs for "straight") |
| Scotch (single malt) | Scotland | 100% malted barley | Used oak (often ex-bourbon or ex-sherry) | 3 years |
| Irish whiskey | Ireland | Malted/unmalted barley (varies) | Used oak | 3 years |
| Japanese whisky | Japan (per 2021 industry standard) | Malted grain, mashed/fermented/distilled in Japan | Used oak, often mizunara | 3 years |
Does the Spelling Actually Matter?
A little, as a rule of thumb rather than a law. American and Irish producers generally spell it "whiskey" (with an e); Scottish, Japanese, Canadian and Australian producers generally spell it "whisky." Bourbon is American, so it's technically "whiskey" — though you'll see US federal regulations themselves use "whisky" in places, which tells you how loosely this is actually enforced. We use "whisky" through most of this journal because that's the convention here and across most of the categories we sell into, but don't read anything into a stray "e."
Does Any of This Change How You Should Drink It?
Not the glass, particularly — a decent tumbler handles bourbon and Scotch equally well, and we'd say the same about ours as any other. What does change is the water. Bourbon's higher typical bottling strength and sweeter profile mean a few drops of water tend to open it up rather than dilute it away, in the same way a cask-strength Scotch benefits from cutting. If you're new to tasting either style side by side, it's worth reading through the basics before you start second-guessing your own palate — our guide to getting started covers the groundwork we'd want a first-timer to have.
Is bourbon just American Scotch?
No — the production rules are different in ways that matter. Scotch is 100% malted barley in a used barrel; bourbon is corn-dominant in a brand-new charred barrel. They're both whisky, made under different national rulebooks, and they land in genuinely different places.
Can bourbon be made outside the US?
No. Something can be made using bourbon's exact recipe — 51% corn, new charred oak, the lot — anywhere in the world, but it legally cannot be called bourbon unless it's made in the United States. Outside the US it would be labelled a "corn whiskey" or similar.
Is Tennessee whiskey the same as bourbon?
Almost. Tennessee whiskey meets every requirement for bourbon and typically adds one extra step — the Lincoln County Process, filtering the spirit through sugar maple charcoal before barrelling. Most Tennessee whiskey could legally be labelled bourbon; producers just choose not to.
Why does bourbon taste different bottle to bottle if the rules are so strict?
Because the rules set a floor, not a recipe. Two bourbons can both be 51% corn and new charred oak and still taste completely different depending on the exact mash bill, the yeast strain, barrel char level, warehouse location and how long it's aged. The regulation defines the category — it doesn't define the flavour.