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What’s The Difference Between Bourbon and Sour Mash? (2024)

What’s The Difference Between Bourbon and Sour Mash

Last Updated on April 13, 2024 by Lydia Martin

Ah, bourbon-the nectar of the Gods and the water of life, a smooth, complex spirit that Americans have enjoyed for centuries. 

But what exactly is bourbon, and why is it confused with sour mash? Is there a difference between bourbon and sour mash? Here’s the answer! 

Sour Mash & Bourbon Compared

Michter's Sour Mash Whiskey

Sour mash basically refers to a particular process used by distillers to add a specific flavor to the whiskey. Bourbon is a category of American whiskey made following distinct requirements and restrictions.

A sour mash whiskey can be classified as bourbon if it is made under the same bourbon restrictions (51% corn, aged in new charred oak barrels, etc).

A whiskey maker makes sour mash whiskey by adding a portion of still-fermenting mash to the new batch of spirits. On the other hand, bourbon uses all new ingredients for each batch. It gives the bourbon a sweeter flavor profile. As a result, bourbon typically has richer color and deeper flavor than sour mash whiskey. 

Here’s A Closer Look

Here's A Closer Look


James C. Crow is credited with developing the sour mashing process in the early 1800s. He discovered that he could easily control the fermentation process by using a portion of mash from the last batch of spirit. The sour mash refers to the process where the previously fermented mash is used for new batches, just like the starter in sourdough bread. 

Bourbon has a long and rich history in the United States, dating back to the early days of American settlement. Made in Kentucky, it gets its name from bourbon county. Moreso, it is made from a mash of corn, rye, and barley and matured in new oak barrels.

Production & Distillation

Bourbon Mash Bill Process

The sour mash whiskey adds some of the spent grain from the previous batch of spirit into the fermented mash like sourdough bread. The process is like a sourdough starter that adds beneficial bacteria and enzymes which help to break down the starches and sugars in the grain. The sour mash is then distilled and aged in new charred oak barrels. 

Bourbon whiskey comes from grain mash, typically corn, rye, and barley. It is aged in new charred oak barrels for at least two years (straight bourbon), but it can be aged for much longer. In fact, there is no aging requirement for a whiskey to be called bourbon [1].

Jack Daniel’s uses a bourbon recipe, but it has a different distillation process because it uses the Lincoln County Process and whiskey sour mash. 

Alcohol Content

Bourbon whiskey must be distilled to no more than 160 proof (80% alcohol by volume) and bottled at no less than 80 proof (40% alcohol by volume content). It typically has an alcohol content of between 40% and 50% at bottling time. 

Most sour mash whiskeys have an alcohol content of around 40%. It means that they are slightly less alcoholic than other types of whiskey. 


Woodinville Bourbon

Major bourbon and Tennessee whiskeys use the sour mash technique in their production. A portion of the fermented grain mixture from the last batch of whiskey starts the fermentation process for the new batches. 

Also, it is used to produce other types of whiskey, including Tennessee whiskey, and they specify it on their labels. Tennessee whiskey distilleries like Jack Daniel’s put a label on their Tennessee whiskey bottles. 

The label is one of the most important aspects of any straight bourbon bottle. It tells the story of the distillery, the distiller, and the bourbon itself. Moreso, the label must include the distillery’s name and address and the distiller’s signature.

Mash Bills

The most common bourbon mash contains: 70% corn, 15% rye, and 15% barley; or, 65% corn, 35% rye; or, 51% corn, 37% rye, and 12% barley. While not all whiskey uses the same mash bill, the final product must be made with at least 51% corn to be called bourbon.

On the other hand, the term sour mash is used to describe a mash used in the distillation process, which is a combination of water, yeast, and grain.

The said combination is removed from an older batch of alcohol to start the fermentation of a new batch. Check out the most popular sour mash whiskeys here.


Is bourbon made from sour mash?

No, bourbon is not made from sour mash. However, some types of bourbons use the sour mash process. The sour mash process helps control the pH level of the fermenting alcohol before adding live yeast.

Is Maker’s Mark a sour mash whiskey?

Yes, Maker’s Mark is a sour mash whiskey. The sour mash bourbon uses some residual yeast and mashed grains from the last batch. It allows for a more consistent flavor profile from batch to batch.

Is bourbon the same as sour mash?

Bourbon and sour mash are closely related, yet distinct. Bourbon is a type of whiskey that must meet specific legal requirements, such as being made primarily from corn, aged in new charred oak barrels, and produced in the United States. Sour mash, on the other hand, refers to a process rather than a specific type of whiskey. In the sour mash process, a portion of previously fermented mash (grain mixture) is added to the new batch to control acidity and promote consistency. While many bourbons use the sour mash process, not all sour mash whiskeys are bourbon. Therefore, while bourbon often utilizes the sour mash method, they are not interchangeable terms.

Is Jack Daniel’s bourbon or sour mash?

Jack Daniel’s is not classified as bourbon but rather as Tennessee whiskey. While it shares similarities with bourbon in terms of ingredients and production process, it undergoes an additional step known as the Lincoln County Process, which involves filtering the whiskey through charcoal before aging, giving it a distinctive flavor profile. So, to answer the question, Jack Daniel’s is not bourbon but rather a type of Tennessee whiskey.

What’s the difference between bourbon and whiskey?

Whiskey is an umbrella term for distilled alcoholic beverages made from fermented grain mash. Bourbon is a specific type of whiskey, differentiated by its mash bill (primarily corn), aging process (in new charred oak barrels), and geographic origin (United States). While all bourbons are whiskey, not all whiskeys are bourbon. Other types of whiskey include Scotch whisky, Irish whiskey, and rye whiskey, each with their own distinct characteristics and production methods.

Is bourbon Sweet or Bitter?

Bourbon is typically associated with sweetness rather than bitterness. Its flavor profile often includes notes of caramel, vanilla, and oak, imparted by the aging process in charred oak barrels. While bourbon can have a slight bitterness due to its high alcohol content and the charred wood, this bitterness is usually balanced by the sweetness from the corn and other grains used in the mash bill. Additionally, some bourbons may exhibit more complex flavor profiles with hints of spice, fruit, or nuttiness, but sweetness tends to dominate. Overall, bourbon is known for its smooth and rich taste, making it a popular choice for sipping neat or in cocktails.

Is Jack Daniel’s a bourbon?

No, Jack Daniel’s is not classified as bourbon; it is categorized as Tennessee whiskey. While both bourbon and Tennessee whiskey share similar production methods and ingredients, there are key differences. One significant distinction is the extra step in the production of Tennessee whiskey known as the Lincoln County Process, where the whiskey is filtered through charcoal before aging. This process imparts a unique flavor profile to Tennessee whiskey, including Jack Daniel’s, setting it apart from bourbon.

Why is Jack Daniel’s not a bourbon?

Jack Daniel’s is not considered bourbon primarily because it undergoes the additional step of charcoal filtering, known as the Lincoln County Process. This extra filtration process distinguishes Tennessee whiskey, including Jack Daniel’s, from bourbon. While both bourbon and Tennessee whiskey share many similarities in terms of ingredients and production methods, this additional step alters the flavor profile of Jack Daniel’s, making it distinct from traditional bourbon.

Why is bourbon called sour mash?

Bourbon is called “sour mash” because of the process used in its production. The sour mash process involves using a portion of previously fermented mash (grain mixture) in the new batch to control acidity and promote consistency in fermentation. This technique helps to maintain a stable pH level in the fermentation process, which is crucial for producing quality bourbon. While the term “sour” might suggest a tangy or acidic flavor, it actually refers to the sour mash’s role in regulating acidity rather than imparting a sour taste to the final product. Sour mash is a traditional method used in bourbon production, contributing to the characteristic flavor profile and consistency of this beloved American whiskey.

Is Johnnie Walker a bourbon?

No, Johnnie Walker is not a bourbon; it is a brand of Scotch whisky. Scotch whisky is produced in Scotland and has its own set of regulations and standards that differ from those of bourbon. While bourbon is primarily made from corn and aged in new charred oak barrels, Scotch whisky is typically made from malted barley and aged in used oak barrels. Additionally, Scotch whisky often exhibits distinct smoky and peaty flavors, which are characteristic of whiskies produced in Scotland’s diverse regions. Therefore, Johnnie Walker, as a Scotch whisky brand, is not classified as bourbon.

Difference Between Bourbon and Sour – Summary

All bourbon and sour mash is whiskey, but not all sour mash is bourbon. There is a difference between bourbon and sour mash, but it’s not really logical to compare them. 

Sour mashing is a process used in different types of whiskey like rye whiskey, bourbon, and Tennessee whiskey. To make sour mash whiskey, a portion of the “mash,” or grain mixture, from a previous batch of whiskey is used as the starter for the new batch. It adds bacteria to the new mash, which helps to create a unique flavor profile.

Meanwhile, to be called bourbon, whiskey needs to follow strict requirements. 


  1. Rules That Make It Bourbon
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