How long must a straight bourbon be aged?

"Straight bourbon" has the same 51% corn mash and must also spend at least 2 years in charred new oak barrels. (Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (5), last checked Oct 30, 2026.)

What makes a whisky Scotch?

Scotch whisky must be distilled at a distillery in Scotland from water and malted barley, to which only whole grains of other cereals may be added. (Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1)(a), last checked Oct 30, 2026.)

How long must Irish whiskey be matured?

It must be matured in wooden casks in a warehouse in Ireland or Northern Ireland, for at least three years in total. (Source: Irish Whiskey Act, 1980 (No. 33 of 1980), section 1(3), last checked Oct 30, 2026.)

Is Japanese whisky defined by law?

This is the association's own voluntary standard, set on 12 February 2021. Its English translation says it is not legally binding. (Source: Standards for Labeling Japanese Whisky, Article 5 (JSLMA, voluntary standard), last checked Oct 30, 2026.)

Guide · Whiskey

Whiskey: what bourbon, rye, Scotch, Irish, Canadian and Japanese whisky mean

Information only, not legal advice. Rules change; check the source. Last checked Oct 30, 2026.

The short version

Each country writes its own whisky rules, so bourbon, Scotch, Irish whiskey and Canadian whisky do not mean the same things.

In the United States, bourbon needs a mash of at least 51% corn and charred new oak barrels, rye needs a mash of at least 51% rye, and "straight" adds at least 2 years in barrel.

Scotch must be made in Scotland from water and malted barley and matured there for at least three years, and Irish whiskey and whisky sold in Canada also have a three-year minimum.

Japanese whisky is defined by a voluntary industry standard, not by a law we have read.

This guide covers the United States, Scotland, Ireland, Canada and Japan. Other whisky countries are not covered. "Whisky" and "whiskey" are both used because the sources spell it both ways.

LEGAL Written in a law, a regulation or an official standard.
INDUSTRY STANDARD Written by an industry body. It is voluntary and is not a law.
COMMON USAGE How a name is used in the sources we read. It is not a rule.

The rules

Each rule is written in our own words from the source linked under it. Open a section to read its rules.

Bourbon (United States)

5 rules

LEGAL
Bourbon must be made from a mash that is at least 51% corn.
Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (2) · last checked Oct 30, 2026
LEGAL
It must be distilled at no more than 160 proof and put into charred new oak barrels at no more than 125 proof.
Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (2) · last checked Oct 30, 2026
LEGAL
The word "bourbon" may not be used for a whisky that was not both distilled and aged in the United States.
Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (2) · last checked Oct 30, 2026
LEGAL
"Straight bourbon" has the same 51% corn mash and must also spend at least 2 years in charred new oak barrels.
Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (5) · last checked Oct 30, 2026
LEGAL
American whiskies like these must be bottled at 40% alcohol by volume or more.
Source: 27 CFR 5.143(a) · last checked Oct 30, 2026

Rye (United States)

2 rules

LEGAL
American rye whisky must be made from a mash that is at least 51% rye, distilled at no more than 160 proof, and put into charred new oak barrels at no more than 125 proof.
Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (2) · last checked Oct 30, 2026
LEGAL
"Straight rye" has the same 51% rye mash and must also spend at least 2 years in charred new oak barrels.
Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (5) · last checked Oct 30, 2026

Tennessee whiskey

1 rule

LEGAL
We found no federal definition of Tennessee whiskey in the American whisky rules we read, so no mash or process rule for it comes from federal law. The only mention of Tennessee there bars the state name from light whisky labels.
Source: 27 CFR 5.66(f)(3) and 5.143(c) · last checked Oct 30, 2026

Scotch

8 rules

LEGAL
Scotch whisky must be distilled at a distillery in Scotland from water and malted barley, to which only whole grains of other cereals may be added.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1)(a) · last checked Oct 30, 2026
LEGAL
It must be matured only in oak casks of no more than 700 litres, only in Scotland, for at least three years.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1)(a) · last checked Oct 30, 2026
LEGAL
It must be at least 40% alcohol by volume when bottled, and it must have been distilled at less than 94.8%.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1)(a) · last checked Oct 30, 2026
LEGAL
Single malt Scotch whisky is Scotch distilled at a single distillery, in pot stills, from water and malted barley with no other cereals added.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1) and (2) · last checked Oct 30, 2026
LEGAL
Single grain Scotch whisky is Scotch distilled at a single distillery that is not a single malt; the regulations' full definition is longer, so check the source.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1) and (2) · last checked Oct 30, 2026
LEGAL
Blended malt Scotch whisky is a blend of two or more single malts from more than one distillery.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1) and (2) · last checked Oct 30, 2026
LEGAL
Blended Scotch whisky is a blend of one or more single malts with one or more single grain Scotch whiskies.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1) and (2) · last checked Oct 30, 2026
LEGAL
Blended grain Scotch whisky is a blend of two or more single grain Scotch whiskies from more than one distillery.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1) and (2) · last checked Oct 30, 2026

Irish whiskey

3 rules

LEGAL
Irish whiskey is distilled in Ireland or Northern Ireland from a mash of cereals that has been saccharified by the diastase of the malt in it, fermented with yeast, and distilled at less than 94.8% alcohol by volume.
Source: Irish Whiskey Act, 1980 (No. 33 of 1980), section 1(3) · last checked Oct 30, 2026
LEGAL
It must be matured in wooden casks in a warehouse in Ireland or Northern Ireland, for at least three years in total.
Source: Irish Whiskey Act, 1980 (No. 33 of 1980), section 1(3) · last checked Oct 30, 2026
LEGAL
Blended Irish whiskey is a blend of two or more distillates that each meet that definition.
Source: Irish Whiskey Act, 1980 (No. 33 of 1980), section 1(2) · last checked Oct 30, 2026

Canadian whisky

3 rules

LEGAL
Whisky sold for consumption in Canada, other than bourbon or Tennessee whisky, must be aged at least three years in "small wood", meaning casks or barrels of no more than 700 litres.
Source: Food and Drug Regulations (C.R.C., c. 870), sections B.02.023(1) and B.02.002 (definition of small wood) · last checked Oct 30, 2026
LEGAL
Any age claim for Canadian whisky is limited to the time it spent in small wood.
Source: Food and Drug Regulations (C.R.C., c. 870), sections B.02.023(1) and B.02.002 (definition of small wood) · last checked Oct 30, 2026
LEGAL
The grain requirements in Canada's former definition of whisky (section B.02.010) were repealed in 2024 (SOR/2024-244).
Source: Food and Drug Regulations (C.R.C., c. 870), sections B.02.023(1) and B.02.002 (definition of small wood) · last checked Oct 30, 2026

Japanese whisky

3 rules

INDUSTRY STANDARD
The industry association's labeling standard says Japanese whisky is made only from malted grains, other cereal grains and water extracted in Japan, with malted grains always used.
Source: Standards for Labeling Japanese Whisky, Article 5 (JSLMA, voluntary standard) · last checked Oct 30, 2026
INDUSTRY STANDARD
The same standard requires saccharifying, fermenting and distilling at a distillery in Japan at less than 95% alcohol, maturing in wooden casks of no more than 700 litres in Japan for at least 3 years, and bottling only in Japan at 40% alcohol or more.
Source: Standards for Labeling Japanese Whisky, Article 5 (JSLMA, voluntary standard) · last checked Oct 30, 2026
INDUSTRY STANDARD
This is the association's own voluntary standard, set on 12 February 2021. Its English translation says it is not legally binding.
Source: Standards for Labeling Japanese Whisky, Article 5 (JSLMA, voluntary standard) · last checked Oct 30, 2026

What the label tells you

Words you may see on a bottle, and what they mean under the rules above.

LEGAL Bourbon
Under the American rules, a mash of at least 51% corn, in charred new oak. The word may not be used for a whisky that was not both distilled and aged in the United States.
Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (2) · last checked Oct 30, 2026
LEGAL Straight (bourbon or rye)
At least 2 years in charred new oak barrels. The table we read lists no minimum time for plain bourbon or rye.
Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (5) · last checked Oct 30, 2026
LEGAL Rye (American)
A mash of at least 51% rye.
Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (2) · last checked Oct 30, 2026
LEGAL Tennessee whiskey
We found no federal definition. Tennessee's own law is not read here.
Source: 27 CFR 5.66(f)(3) and 5.143(c) · last checked Oct 30, 2026
LEGAL Scotch
Distilled in Scotland from water and malted barley; matured in Scotland for at least three years.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1)(a) · last checked Oct 30, 2026
LEGAL Single malt (Scotch)
One distillery, malted barley only, pot stills.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1) and (2) · last checked Oct 30, 2026
LEGAL Blended Scotch / blended malt / blended grain
Blends of single malts and/or single grain whiskies; see the rules for which combination each name means.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1) and (2) · last checked Oct 30, 2026
LEGAL Irish whiskey
Distilled in Ireland or Northern Ireland; matured in wooden casks there for at least three years.
Source: Irish Whiskey Act, 1980 (No. 33 of 1980), section 1(3) · last checked Oct 30, 2026
LEGAL Canadian whisky
The age rule is for any whisky sold in Canada: three years in small wood. We have not read where Canada now sets grain content.
Source: Food and Drug Regulations (C.R.C., c. 870), sections B.02.023(1) and B.02.002 (definition of small wood) · last checked Oct 30, 2026
LEGAL Age statement on Canadian whisky
An age claim can count only the time in small wood.
Source: Food and Drug Regulations (C.R.C., c. 870), sections B.02.023(1) and B.02.002 (definition of small wood) · last checked Oct 30, 2026
INDUSTRY STANDARD Japanese whisky
A voluntary industry standard, not a law.
Source: Standards for Labeling Japanese Whisky, Article 5 (JSLMA, voluntary standard) · last checked Oct 30, 2026

Glossary and term finder

Find a term

Blended malt (Scotch) LEGAL
A blend of single malts from more than one distillery.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1) and (2) · last checked Oct 30, 2026
Mash LEGAL
The grain mixture that is fermented before distilling. American rules set a minimum share for the named grain, not a full recipe.
Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (2) · last checked Oct 30, 2026
Single grain (Scotch) LEGAL
Scotch from one distillery that is not a single malt.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1) and (2) · last checked Oct 30, 2026
Single malt (Scotch) LEGAL
Scotch from one distillery, made from water and malted barley only, in pot stills.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1) and (2) · last checked Oct 30, 2026
Small wood LEGAL
Canada's term for casks or barrels of no more than 700 litres.
Source: Food and Drug Regulations (C.R.C., c. 870), sections B.02.023(1) and B.02.002 (definition of small wood) · last checked Oct 30, 2026
Straight LEGAL
For American bourbon and rye: at least 2 years in charred new oak barrels.
Source: 27 CFR 5.143(c) Whisky, Table 1 to paragraph (c), type (5) · last checked Oct 30, 2026
Voluntary standard INDUSTRY STANDARD
A standard set by an industry body that is not a law. Japan's labeling standard for whisky is one.
Source: Standards for Labeling Japanese Whisky, Article 5 (JSLMA, voluntary standard) · last checked Oct 30, 2026

What we do not know yet

These are things we have not read or have not checked. Where a rule is not listed above, treat it as unknown to us, not as absent.

We have not read Tennessee's own law on Tennessee whiskey.
Source: 27 CFR 5.143 (eCFR) · last checked Oct 30, 2026
We have not written up every American whisky type in 27 CFR 5.143, for example the type for whisky distilled from a bourbon, rye, wheat or malt mash.
Source: 27 CFR 5.143 (eCFR) · last checked Oct 30, 2026
We have not checked whether the federal text has changed since we read it on the date shown.
Source: 27 CFR 5.143 (eCFR) · last checked Oct 30, 2026
We have not checked whether the Scotch Whisky Regulations 2009 have been amended since we read them, and we have not compared how regulation 3 reads in each part of the United Kingdom.
Source: The Scotch Whisky Regulations 2009 (SI 2009/2890), regulation 3(1)(a) · last checked Oct 30, 2026
We have not read the Irish Whiskey geographical indication technical file, which defines single pot still, single malt and grain whiskey, and we have not checked for amendments to the 1980 Act.
Source: Irish Whiskey Act, 1980 (No. 33 of 1980), section 1(3) · last checked Oct 30, 2026
We have not found where Canada now sets the grain content of Canadian whisky after the old definition was repealed, and we have not read Canada's rules on the name "Canadian rye".
Source: Food and Drug Regulations (C.R.C., c. 870), sections B.02.023(1) and B.02.002 (definition of small wood) · last checked Oct 30, 2026
We have not read the Fair Competition Code on the Labeling of Whisky (1980) or the Liquor Tax Act's definition of whisky, and we read only the association's English translation of its standard, not the Japanese original.
Source: Standards for Labeling Japanese Whisky, Article 5 (JSLMA, voluntary standard) · last checked Oct 30, 2026

Looking for a bottle?

Information only, not legal advice. Rules change; check the source.