Liquor Laboratory

Cracking the Code: What is a Bourbon Mash Bill?

Screenshot 2023-07-12 at 11.20.11 PM

Last Updated on August 21, 2023 by Lydia Martin


What is a mash bill?

A mash bill refers to the combination of grains used in the production of whiskey, particularly bourbon. It outlines the specific types of grains and their proportions that are used during the mashing and fermentation stages of whiskey production. The mash bill is a crucial component in determining the flavor, character, and legal classification of the whiskey.

What is bourbon as a type of whiskey?

Bourbon is a specific type of whiskey that holds a distinct place in the world of spirits. It is primarily produced in the United States and has a set of legal requirements that must be met to be considered bourbon.

Bourbon is known for its rich and full-bodied flavor profile, often characterized by notes of caramel, vanilla, oak, and varying sweetness levels. To be classified as bourbon, the whiskey must meet the following criteria [1]:

  • Mash Bill: The mash bill must contain at least 51% corn. This high corn content contributes to the sweetness and smoothness typically associated with bourbon.
  • Aging: Bourbon must be aged in new, charred oak barrels. The aging process allows the whiskey to develop complex flavors and aromas as it interacts with the wood.
  • Distillation: Bourbon must be distilled to no more than 160 proof (80% alcohol by volume) and entered into the barrel for aging at no more than 125 barrel entry proof (62.5% alcohol by volume).
  • Bottling Strength: Bourbon is usually bottled at a minimum of 80 proof (40% alcohol by volume) but can be higher depending on the producer’s preference.

Bourbon is special in American history and culture, often associated with Kentucky, although it can be produced anywhere in the United States. Its popularity has spread globally, captivating whiskey enthusiasts with its diverse flavors and craftsmanship.

Definition and Purpose

What is a bourbon mash bill?

A mash bill refers to the combination of grains used to produce bourbon whiskey. It determines the types of grains and their proportions and plays a pivotal role in establishing the character and flavor of the final product.

Why is the mash bill important in bourbon production?

The mash bill is a fundamental aspect of bourbon production, laying the foundation for the whiskey’s taste, aroma, and overall character. It defines the grain profile and acts as a key differentiator among various bourbon brands.

How does the mash bill impact the flavor of bourbon?

The mash bill directly influences the flavor of bourbon by imparting distinct characteristics from the chosen grains. The proportions of grains contribute to the sweetness, spiciness, and complexity of the whiskey, giving each bourbon a unique flavor profile.


Primary grain: What is the main grain used in bourbon mash bills?

Corn takes center stage as the primary grain in bourbon mash bills, contributing to its sweetness, full-bodied texture, and characteristic smoothness. It is a requirement that bourbon mash bills contain at least 51% corn.

Secondary grains: What are the other grains used in bourbon mash bills?

Secondary grains typically include rye, wheat, and malted barley. Rye adds spiciness and complexity, while wheat contributes to a softer and smoother mouthfeel. Malted barley aids in the fermentation process by providing essential enzymes.

How do the proportions of grains affect the mash bill?

The proportions of flavoring grain in a mash bill significantly impact the final flavor profile of bourbon. Higher corn content results in sweeter bourbons, while greater proportions of rye or wheat lend spiciness or smoothness, respectively.

Legal Requirements

What are the legal requirements for bourbon mash bills in the United States?

For a whiskey to be classified as bourbon in the United States, it must adhere to specific legal requirements. These include being made from a mash bill that contains at least 51% corn and is aged in new, charred oak bourbon barrels. [2]

How does the mash bill contribute to meeting the criteria for bourbon classification?

The mash bill’s composition is critical for meeting the legal requirements of bourbon. The minimum 51% corn content is essential to ensure the sweetness and distinctive characteristics associated with bourbon.

Variations and Distinctions

What are the differences in mash bills between different bourbon brands?

Bourbon brands often distinguish themselves by crafting unique mash bills. Some brands favor higher rye content for spicier profiles, while others experiment with wheat for a smoother taste. These variations allow for diverse bourbon options, from rye to wheated bourbon.

What is the impact of different mash bills on flavor profiles?

By altering the proportions of grains, distilleries can achieve a wide range of flavor profiles. Low rye mashbill delivers bold and peppery flavor notes, while high rye mash bills introduce a captivating spice.

Moreover, those heavier on corn taste sweeter and richer bourbons. The variations are seemingly endless.

Single grain vs. blended grain bourbons: How does the mash bill factor into the distinction?

Mash bills play a crucial role in distinguishing single-grain and blended-grain bourbons. Single-grain bourbons use predominantly one grain, like corn, for a focused flavor profile. Blended grain bourbons combine multiple grains to achieve a more nuanced and complex taste.

a shot of bourbon on the rocks being served at a party

Factors Influencing Mash Bill Choices

What are the traditional recipes and regional preferences?

Bourbon’s rich history is intertwined with traditional recipes and regional preferences. Distilleries often draw inspiration from historical mash bills in making various bourbons, from rye to wheated bourbons, paying homage to time-honored traditions while catering to local tastes.

What are the experimental and innovative mash bills?

Innovation drives the bourbon industry forward, and distillers frequently experiment with unconventional mash bills. These endeavors push boundaries and allow for the creation of unique and groundbreaking expressions.

What are the market trends and consumer preferences?

Consumer preferences and market trends shape distillers’ choices when crafting their mash bills. Distilleries strive to cater to evolving consumer tastes while also maintaining the core characteristics that define bourbon.


What is an example of mash bill?

An example of a bourbon’s mash bill is 70% corn, 15% rye, and 15% malted barley. Distillers can showcase their versatility and craftsmanship by experimenting with different mash bills at the same distillery.

The grain percentage showcases a high corn content, contributing to the sweetness and richness often associated with bourbon.

The inclusion of rye adds spiciness and complexity, while malted barley provides essential enzymes for the fermentation of the bourbon making process.

What are the ingredients in a mash bill?

The ingredients in a mash bill for bourbon typically include:

  • Corn: Corn is the primary grain used in bourbon mash bills. It provides a sweet and full-bodied flavor profile.
  • Rye: Rye is commonly added to bourbon mash bills to add spiciness and complexity to the whiskey. It imparts a peppery and robust character.
  • Malted Barley: Malted barley is used in bourbon mash bills to provide enzymes necessary for the fermentation process. It helps convert starches into fermentable sugars.

a shot of bourbon prepared by the bartender

How does mash bill affect taste?

The mash bill is a key determinant of the taste experience when it comes to bourbon. It dictates the balance of sweetness, spiciness, and complexity, allowing distillers to create a wide range of flavor profiles to cater to various preferences and styles.

How does mash tun affect the bourbon flavor?

The mash tun affects bourbon flavor by extracting flavors from the grains, controlling temperature during mashing, determining fermentable sugar content, and influencing the grain-to-water ratio. It plays a vital role in shaping the unique taste and character of bourbon.


Lumint ad Side Bar
Flex Ad Side Bar