Whiskey is a spirit distilled from fermented grain and aged in wood \u2014 but within that definition live a dozen legally distinct categories. The main types are bourbon, rye, Tennessee whiskey, Scotch (single malt and blended), Irish whiskey, Japanese whisky and Canadian whisky<\/strong>, each defined by its grain bill, distillation rules, cask type and geography. This guide explains what separates them, and adds the perspective most guides skip: which bottle formats each category actually uses, from 700 mL European standards to 1.75 L American handles.<\/p>\n\n Both are correct \u2014 the spelling follows geography. Whiskey<\/strong> (with an “e”) is used in the United States and Ireland; whisky<\/strong> is used in Scotland, Japan, Canada and most of the rest of the world. The spelling on a label is a quick clue to origin, and a labeling detail export brands must get right for each market.<\/p>\n\n Legal definitions summarized; full category rules are set by each country’s regulations (TTB standards of identity in the US, the Scotch Whisky Regulations in the UK, etc.).<\/em><\/p>\n\n Bourbon<\/strong> must be made from at least 51% corn, distilled to no more than 80% ABV, and aged in new<\/em> charred oak containers \u2014 the rule that gives bourbon its vanilla-caramel profile and, incidentally, supplies the world’s used barrels to every other whiskey category. It can be made anywhere in the US, not only Kentucky. Straight bourbon<\/strong> adds a minimum of two years’ aging.<\/p>\n Rye whiskey<\/strong> follows the same rules with at least 51% rye grain, trading sweetness for spice and pepper. Tennessee whiskey<\/strong> meets bourbon’s requirements plus the Lincoln County Process \u2014 filtering the new-make spirit through sugar-maple charcoal before barreling.<\/p>\n Packaging note: American whiskeys live on the 750 mL fifth at home, but any brand exporting to Europe needs a 700 mL variant \u2014 a 50 mL difference that means separate label declarations, adjusted fill lines and sometimes a second bottle reference. Our bottle size guide<\/a> covers the 700 vs 750 mL decision in detail.<\/p>\n\n Scotch must be distilled and matured in Scotland for at least three years in oak casks. Single malt<\/strong> means 100% malted barley from a single distillery in pot stills; single grain<\/strong> allows other cereals and column stills; blended Scotch<\/strong> \u2014 the bulk of the market \u2014 marries malt and grain whiskies. Regional styles (peaty Islay, lighter Speyside, maritime Highlands) are conventions rather than legal categories, but they drive strong shelf identities \u2014 and correspondingly distinctive bottle shapes, from tall Speyside rounds to heavy-based premium malts.<\/p>\n\n Irish whiskey must be distilled and matured on the island of Ireland for at least three years. Triple distillation is traditional (though not mandatory), producing a smoother, lighter profile. The category’s signature single pot still<\/strong> style \u2014 a mash of malted and unmalted barley \u2014 exists nowhere else and anchors the premium end of the market.<\/p>\n\n Japanese whisky historically borrowed Scotch methods; since the 2021 industry labeling standards, spirits labeled “Japanese whisky” must be mashed, fermented, distilled and aged at least three years in Japan. The domestic market also runs a distinctive bottle format \u2014 720 mL<\/strong>, inherited from sake measures \u2014 alongside 700 mL for export, a nuance that matters to any distillery targeting both shelves.<\/p>\n\n Canadian whisky must age at least three years in small wood and is typically a blend of high-proof base whisky and flavorful rye-heavy flavoring whiskies \u2014 which is why Canadians often call it “rye” regardless of the actual grain bill. It ships mostly in 750 mL, with a domestic 1.14 L format unique to the market.<\/p>\n\nWhiskey or whisky? The spelling rule<\/h2>\n
The main types of whiskey at a glance<\/h2>\n
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Type<\/th> Origen<\/th> Key legal requirements<\/th> Typical retail bottle<\/th><\/tr><\/thead>\n Bourbon<\/td> USA<\/td> \u2265 51% corn; new charred oak barrels; \u2264 80% ABV distillation; no additives<\/td> 750 mL (US); 700 mL for EU export<\/td><\/tr>\n Rye whiskey (US)<\/td> USA<\/td> \u2265 51% rye; new charred oak barrels<\/td> 750 mL<\/td><\/tr>\n Tennessee whiskey<\/td> USA (Tennessee)<\/td> Bourbon rules + Lincoln County Process (charcoal mellowing)<\/td> 750 mL; 1.75 L value formats<\/td><\/tr>\n Scotch \u2014 single malt<\/td> Scotland<\/td> 100% malted barley; one distillery; pot stills; \u2265 3 years in oak<\/td> 700 mL (70 cl)<\/td><\/tr>\n Scotch \u2014 blended<\/td> Scotland<\/td> Blend of malt and grain whiskies; \u2265 3 years in oak<\/td> 700 mL; 1 L travel retail<\/td><\/tr>\n Irish whiskey<\/td> Irlanda<\/td> \u2265 3 years in wooden casks; often triple-distilled<\/td> 700 mL<\/td><\/tr>\n Japanese whisky<\/td> Jap\u00f3n<\/td> Since 2021 standards: mashed, distilled and aged \u2265 3 years in Japan<\/td> 700 mL; 720 mL domestic<\/td><\/tr>\n Canadian whisky<\/td> Canad\u00e1<\/td> \u2265 3 years in small wood; typically blended, rye-influenced<\/td> 750 mL; 1.14 L domestic format<\/td><\/tr>\n <\/tbody>\n<\/table>\n American whiskeys: bourbon, rye and Tennessee<\/h2>\n
Scotch whisky: single malt, single grain and blends<\/h2>\n
Irish whiskey<\/h2>\n
Japanese whisky<\/h2>\n
Canadian whisky<\/h2>\n
Why whiskey categories map to bottle formats<\/h2>\n