Legal definitions and production rules

Under the North American Free Trade Agreement of 1994, Tennessee whiskey can be classified as Bourbon, although a number of well-known Tennessee whiskey producers opt not to use the term. Other states which produce Bourbon include New York, Virginia, Illinois, Colorado and Massachusetts.

There is no standard, international definition of Bourbon as a whiskey style, although a number of governments (notably the US, Canada and the EU) have laws protecting the name and its usage. In most countries, any spirit labeled as Bourbon must have been produced exclusively in the US.

Interestingly, the US’s own Bourbon labeling laws apply only to those products sold domestically, and not those destined for export. Under US law, the definition of Bourbon whiskey is “whiskey produced at not exceeding 160° proof from a fermented mash of not less than 51 percent corn and stored at not more than 125° proof in charred new oak containers”. The vast majority of bourbons far exceed the 51 percent minimum corn content and most are bottled with between 40 and 50 percent alcohol ABV (80° and 87.5° proof).

Ageing Bourbon in barrels

Bourbon’s vanilla aroma and gentle sweetness is what distinguishes it from most other whisky/whiskey styles. This comes from its aging in flame-charred, virgin American oak barrels.

There is no official period for which bourbon must be matured, although to be labeled as “Straight Bourbon”, it must spend at least two years in barrel. “Straight” is quite distinct from “neat” in this context. After use, Bourbon barrels are often shipped to Scotland where they are used for ageing Scotch whiskies, particularly Single Malts.

Leading Bourbon brands

The largest distiller of Bourbon in terms of volume is Jim Beam which has been distillery the liquor since 1875. The company’s flagship product is made from a mash of rye, corn and barley.

The Jim Beam brand is owned by parent company Beam Suntory of which also owns Maker’s Mark, Knob Creek, Legent and Booker’s Bourbon.

According to the Wine-Searcher database, the most popular brands of Bourbon are Blanton’s, George T. Stagg, Eagle Rare and Old Rip Van Winkle.