Although we cover the definition of bourbon in greater detail in our introductory guide, let’s quickly refresh our memories of the criteria of basic bourbon whiskey.
Firstly, it must conform to the definition of American whiskey according to the Alcohol and Tobacco Tax and Trade Bureau’s Federal Standard of Identity for Distilled Spirits.
In all cases, the whiskey must be distilled to a maximum of 80% ABV to prevent any loss of flavour, which can be achieved with a pot or column still. Afterwards, it must be aged in new charred oak barrels at no more than 62.5% ABV. However, there is no minimum, ageing period.
All American whiskey can only be bottled at a minimum of 40% ABV while higher percentages are also allowed.
Whiskey is made by distilling fermented beer called a mash bill, which consists of several different types of grain. In order for it to qualify as bourbon, corn should make up at least 51% of the mash.
Producers are free to use any combination of rye, barley, wheat, or even more corn, for the remaining 49%. Meanwhile, there is no specified region for bourbon and it can be made anywhere in the USA.
Some varieties of bourbon may have to follow stricter rules in order to acquire an additional label or certificate. Nevertheless, the above outlines the most basic requirements for a standard bourbon whiskey.
As mentioned above, bourbon whiskey can be legally produced anywhere in the USA. Nevertheless, it does have a strong association with the state of Kentucky.
In fact, over 90% of bourbon producers operate in Kentucky. Indeed, it’s often argued that the water sourced from its limestone-rich soil makes it a unique terroir and, therefore, worthy of its own appellation.
In order to qualify as Kentucky whiskey, the distillery must be located within the state. However, the grain may be sourced from elsewhere.
Otherwise, the whiskey must follow the basic American whiskey and bourbon regulations in order to be recognised as “Kentucky bourbon whiskey”. However, it must also undergo a one-year minimum ageing process.
Likewise, Tennessee has a rich bourbon heritage but rather than use the permitted term “Tennessee Bourbon”, producers often distinguish themselves with the more generic “Tennessee Whiskey”.
A particularly well-known example of this choice of nomenclature is Jack Daniel while George Dickel is representative of its more premium market. A distinguishing feature of Tennessee Whiskey is that it includes the use of a filtering technique called the “Lincoln County Process”.
Before being casked in new oak barrels, the distillate is filtered through charcoal chips, which are often produced from maple wood. The process is often done slowly in order to impart additional flavours and sometimes the charcoal “chips” can be as large as two-by-two timber.
Tennesseans might, therefore, claim that their whiskey is a distinctive product and not a type of bourbon. Until 2013, Tennessee Whiskey didn’t technically have a legal definition apart from a brief mention in the North America Free Trade Agreement.
Furthermore, not all producers used the Lincoln County Process at the time, which made it difficult to underline it as its identifying characteristic.
For this reason, the governor of Tennessee signed House Bill 1084, which requires all local producers to follow the process if they wish to continue using the name. An exception, however, was made for Benjamin Prichard’s Tennessee Whiskey as it’s specifically known to not use the charcoal filtering process.
In some ways, American “straight” whiskey may be regarded as a label of quality similar to Scottish “single-malt whisky”. Nevertheless, the two mustn’t be confused as they’re very different.
Single-malt whisky refers to the ingredients and where they were distilled. In short, it indicates that the whisky is 100% malted barley and produced in only one distillery. Meanwhile, “straight” whiskey is largely an age statement similar to cognac’s V.S. (Very Special).
If you know your cognac, you’ll have guessed that straight whiskey has been aged for a minimum of two years in oak barrels. When used in conjunction with “bourbon” whiskey, it builds upon the basic standards with additional regulations.
For instance, if it has been aged for less than four years, it must clearly feature an age statement. A whiskey aged for longer doesn’t require an age statement and if it fulfils other regulations, it may be labelled as a bonded whiskey as described below.
Straight bourbon may be mixed with other straight bourbons as long as they were distilled in the same state. For this reason, an age statement must represent the youngest whiskey used. Typically, the terms “mixing” or “mingling” are used to avoid confusion with blended bourbon.
Furthermore, straight whiskey may not contain any additional colouring or flavouring agents like caramel or similar. However, other types of bourbon whiskeys may legally do so.
Straight whiskey isn’t exclusive to bourbon. In fact, other primarily rye or barley-based may also use the term if it respects the federal Standards of Identity for Distilled Spirits.
Small-Batch & Single-Barrel Bourbon
While similar in principle, small-batch and single-barrel bourbon are quite different. In both cases, they are produced as premium types of bourbon whiskey. Since they are offered in small and selected quantities, it often implies rarity and exclusivity.
Since there are no regulations that define small-batch whiskey, it may be used to indicate several different criteria. For instance, it may indicate a whiskey made from a mash bill prepared in a smaller quantity or a limited series of barrels that were aged separately from the brand’s main production.
Alternatively, it may instead be the product of a limited pot still run, which is quite rare since most American whiskey is produced using a continuous column still.
Similarly, it may be a combination of the above techniques. In all cases, it suggests that the process is more labour-intensive given that it results in a smaller and more exclusive quantity of whiskey.
Meanwhile, single-barrel bourbon is much more clearly defined and self-explanatory. Indeed, it is a whiskey that has been bottled from only one barrel rather than a blend of several.
As a result, it is supposed to provide a unique flavour rather than one from a regular production that is intended to be consistent every year.
Sour Mash Bourbon
Made famous by Jack Daniel’s Tennessee Whiskey, sour mash is a technique that can be used for most bourbon whiskey. It consists of reserving a small amount of fermented mash for another batch in the following year.
Typically, spent mash is used as slop or feed for cattle, but in some cases, it can be kept and used again. In order to preserve the mash, it is treated with acid, which produces a distinctive flavour while also preventing bacterial growth.
The overall process isn’t unlike sourdough bread where the older mash is used to ferment a new batch. A key advantage of the process is that it allows producers to ensure greater consistency of flavour between each production every year.
Although the antithesis of small-batch whiskey, sour mash whiskey can still be produced as such if desired. While sour mash whiskey is a technique to ensure consistency, a small batch often denotes a unique flavour profile.
Bottled In Bond Bourbon
The Bottled-in-Bond Act was signed in 1897 and represents one of the first federal government regulations to protect the standards of American whiskey. Today, it’s quite rare compared to straight whiskey and some producers may even regard the labelling term as outdated.
A bonded whiskey must have been aged for at least four years, but it also requires that all the spirit in the bottle must have been distilled in the same season by the same distiller in a single distillery. Its ageing process must then take place in a bonded warehouses where it may be supervised by the US government.
Bonded whiskey must then be bottled at a minimum of 50% rather than 40% ABV. Given that it is essentially a single-vintage whiskey, it offers little in the way of blending spirits to create a unique beverage.
Conversely, it could instead be argued that it results in a whiskey that’s more representative of the distiller’s identity. Indeed, it can also be regarded as a stricter type of single-barrel bourbon.
Like straight whiskey, bottled in bond liquor is not an exclusive term for bourbon and can be used by other American creations.
Although historically more affordable, blended bourbon is surprisingly rarer than it used to be. Generally speaking, blended American whiskey must contain at least 20% straight whiskey.
Its other ingredients may consist of neutral high-proof spirit, colourings, and flavourings, all of which are forbidden in straight whiskey. In the case of blended bourbon, however, the mixture must feature a minimum of 51% straight bourbon whiskey.
Blended whiskey must contain at least 20% straight whiskey. However, blended bourbon must contain at least 51% straight bourbon.
Furthermore, “blended straight bourbon whiskeys” or “a blend of straight bourbon whiskeys” is a mixture of only straight bourbon whiskey. Since the straight whiskey may be sourced from different states, it doesn’t fulfil the criteria for straight bourbon whiskey described above.
High-Rye & Wheated Bourbon
The final variety that we’ll be covering is high-rye bourbon. Although it’s not a regulated category, it suggests a bourbon whiskey where the 51% corn proportion in the mash is complemented by an additional 20% to 35% rye.
Similar to high-rye whiskey is high-wheat or “wheated” bourbon. A high quantity of rye may provide a bourbon whiskey with additional spiciness and depth. Meanwhile, heavy use of wheat can impart a mild and subtle flavour profile.
Now that you have read our introductory bourbon guide, take a deeper dive into our resources!