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Get to know Kentucky's most famous spirit.

Max Bonem
April 25, 2017

Bourbon is American. Bourbon is beautiful. Bourbon is, uh, complicated. While few spirits can match bourbon's devout following, its extensive lexicon does make things a bit confusing for the casual consumer. Here are the 10 terms that every bourbon drinker should know.


The definition, that is. By law, bourbon must be made from a grain mixture that is at least 51 percent corn. Additionally, bourbon is always aged in new charred-oak barrels and distilled to no more than 80 percent ABV. When the raw spirit is pumped into the barrels for aging, it must be no more than 62.5 percent ABV. Later, when it is bottled, bourbon has to be at least 40 percent ABV.

Age Statement

A bourbon's age statement indicates the age of the youngest bourbon in the bottle. For example, a bourbon with an age statement of 10 years is made up entirely of bourbons that are at least 10 years old. Age statements are optional for bourbons older than four years.

Cask Strength

For a bourbon to be considered cask strength, it must not be diluted before being bottled. Cask strengths vary greatly from barrel to barrel, due both to warehouse placement and weather conditions. As such, the strength of a bourbon depends primarily on how much it evaporates while aging. If more alcohol evaporates out, the bourbon will be lower proof. Conversely, if more water evaporates, the final product will be higher proof. 

Bottling Proof

Before most bourbon is bottled, it is diluted to 80 proof (40 percent ABV), which is the lowest the whiskey can be diluted to while still qualifying as a bourbon. This is done by bourbon producers to reduce costs and to make bourbon more palatable, without dilution, to a larger market. However, there are exceptions and a higher proof bourbons are readily available.

Straight Bourbon

This term carries additional legal requirements beyond those of regular bourbon. A straight bourbon must be at least two years old. However, if it's younger than four years, the bottle must carry an age statement that reflects the youngest bourbon in the bottle. Additionally, straight bourbon cannot contain any added colors or flavors.

Mash Bill

A mash bill is a specific bourbon's list of ingredients. While all bourbon must contain at least 51 percent corn, the other 49 percent will vary depending on the distiller. Most bourbons, though, contain a mix of wheat, rye and barley.

High Rye

This denotes a bourbon that contains rye as its second main ingredient behind corn. High-rye bourbon is known for having a spicier and richer flavor than other bourbons. 


A wheater refers to a bourbon that contains wheat as its second main ingredient. Wheated bourbons usually taste sweeter than high-rye versions. 

Sour Mash

Sour mash is made by adding a portion of previously used mash to a fresh batch, similar to using a sourdough starter for bread. This gives the mash a slightly sour aroma, but it doesn't affect the flavor of the finished whiskey. This is done for two reasons: it helps with consistency from batch to batch and this process lowers the batch's pH, which makes the fermentation process more efficient.

Sweet Mash

The very rare sweet mash bourbon occurs when only fresh yeast is added to a batch. This leads to a higher pH and produces flavors you wouldn't find in sour mashes.