Bourbon is an American whiskey made from grain, water and yeast, and aged in charred wood barrels.
The name comes from Bourbon County, Kentucky, where Bourbon was first made. Now, Bourbon can be made anywhere in America, but to be labelled as a Kentucky Straight Bourbon, it must be made in Kentucky. And, if the Bourbon is made for consumption within the United States , there are some standards that must be met for the product to be labelled Bourbon:
- A minimum of 51 % of the grain used must be corn (it’s often higher, 65 to 75 %.) Other grains used are barley, and (usually) rye. Different makers often vary the corn, rye and barley ratio. Sometimes wheat is used instead of rye;
- Must be aged, at least briefly, in new oak barrels that have been charred inside;
- Must distilled to no more that 80% alcohol by volume (160 proof);
- Must start the aging process at no more than 62.5% alcohol by volume (125 proof);
- Must end up being bottled at no more than 40% alcohol by volume (80 proof).
The grain is fermented in water (iron-free water is considered the best to make Bourbon with) for 3 to 4 days, then distilled (usually twice.) The whole process takes about 5 days.
Bourbon is then barrelled into new, white oak barrels that have been charred (barrels cannot be re-used.)
The Bourbon can be called “Straight Bourbon” if it meets the above standards, plus:
- Has no added colouring, flavouring or alcohol;
- Has not been blended;
- Has been aged a minimum of 2 years. If it’s aged under 4 years, then the length of aging must be stated on the label.
Note that a Straight Bourbon doesn’t have to label itself as a “Straight” Bourbon.
Currently (2012), most Bourbons sold today are “Straight Bourbons” aged at least four years, and are based on grain that is 2/3 corn or more.
At least one artisan-style Bourbon, “Hudson Baby Bourbon Whiskey” by Tuthilltown Spirits of New York, is aged only 3 months. Normally, though, the minimum is two years, and the most common is 4 years. After 6 years of aging, about 1/3 of the whiskey will be lost to absorption into the wood and to evaporation through the wood; brewers call this “the angel’s third.” Not many bourbons are aged for much more than 12 years, because after that the oak taste can become overpowering.
51% straight bourbon mixed with less-expensive, neutral tasting grain spirit. Other colouring and flavouring may be added. The age on the label must refer to the age of the youngest Bourbon used in the mix (how young the neutral spirits are doesn’t count, as there is no point in aging them.)
Bourbon taken and bottled from one single barrel. Aged for between 6 and 12 years.
A batch of 20 or fewer selected barrels are mixed to form a “mingle”, which is then bottled. (Normally, the “mingle” will be made from 200 or more barrels.) Aged for between 6 and 12 years.
Bourbon reserved from a previous batch (this is called the “backset”) is added to the grains and water before fermentation. The idea is similar to sourdough, with a portion of the previous batch being used as starter for the next batch. Today, all straight bourbons are made using the sour-mash method.
Jack Daniel’s is a bourbon, but like many “Tennessee Whiskeys”, prefer to market itself as such instead.
 Note that the standards don’t apply for Bourbon that will be exported to countries other than Canada and the European Union, which enforce the American standards. Canada, through the NAFTA trade agreement, and the EU, through Commission Regulation (EC) No 936/2009 of 7 October 2009: “Following agreements between the European Union and the USA and Mexico, the use of descriptions for certain spirit drinks (including “Tennessee Whisky or Tennessee Whiskey”, “Bourbon Whisky or Bourbon Whiskey or Bourbon as a description of Bourbon Whiskey”, “Tequila” and “Mezcal”) must conform to the law in those countries.”
The standards have their roots in the Bottled in Bond Act of 1897, the Pure Food and Drug Act of 1906, and in the “Standards of Identity for Distilled Spirits, U.S. Code of Federal Regulations, Title 27, Part 5” (aka 27 CFR 5), first codified in 1935.
The “made in America” part was added owing to a 1964 congressional resolution made by Senator Thurston Morton and Representative John C. Watts:
“Bourbon whiskey is a distinctive product of the United States and is unlike other types of alcoholic beverages, whether foreign or domestic; and whereas to be entitled to the designation ‘Bourbon whiskey’ the product must conform to the highest standards … and whereas Bourbon whiskey has achieved recognition and acceptance throughout the world as a distinctive product of the United States … it is the sense of Congress that the recognition of Bourbon whiskey as a distinctive product of the United States be brought to the attention of the appropriate agencies.”
The process of charring the barrels started in the 1700s, and was essentially the origin of Bourbon. The story, for what it’s worth, is that a distiller named “Elijah Craig” was barrelling some clear corn whiskey that he’d made in Bourbon County, Kentucky. The barrels were charred — either Craig charred them on purpose as an experiment, or the barrels were in an accidental fire, and Craig decided to use them anyway. The whiskey was transported by river all the way down to New Orleans. By the time it reached there, it had absorbed some of the carmelized sugars from the burnt wood, and taken on an amber colour. People really liked it.
The yeast used by The Maker’s Mark bourbon company dates back to 1842. To keep that particular yeast alive during Prohibition, they stored it at a bakery.
Bourbon isn’t actually made in Bourbon County anymore. Most is now made in Clermont County, Kentucky.
Meece, Mickey. Bourbon’s All-American Roar. New York Times. 24 December 2011.