The Science Behind BourbonBourbon, the iconic American whiskey with its rich, full-bodied flavor, is more than just a drink. It’s a product of meticulous science, traditional processes, and a little bit of magic. This article will take you on a journey from the grain field to the bourbon glass, exploring the fascinating science behind bourbon production.

The Mash Bill

The journey begins with its primary ingredient: corn. By law, at least 51% of a bourbon’s mash bill (the combination of grains used in distillation) must be corn. The remaining percentage is usually a blend of rye, barley, and sometimes wheat. The precise mix depends on the distiller’s recipe and contributes significantly to the final flavor of the bourbon.

The grains are milled into a coarse flour, then mixed with water and cooked to convert the starches into sugars. This process, called saccharification, is vital because yeast, which is added later, feeds on these sugars to produce alcohol.


After the mash is cooled, it’s moved to a fermentation vessel where yeast is added. Yeast consumes the sugars in the mash, producing alcohol, heat, and carbon dioxide in a process known as fermentation.

Different strains of yeast create different flavors during fermentation. Some yield fruity notes, others spicy or nutty flavors. This is why distilleries often guard their yeast strains closely – they’re a big part of what makes each bourbon unique.


Once fermentation is complete, the mixture, now called “distiller’s beer,” moves on to the still. The still heats the beer to a boil. Since alcohol boils at a lower temperature than water, the alcohol turns into vapor first. This vapor is collected and condensed back into liquid form. This liquid, known as “white dog” or “new make,” is clear and contains a high alcohol content.

Bourbon is typically distilled twice: first in a column still, which strips out impurities and increases the alcohol content, and then in a pot still, which allows for more control over the final flavor.


Now comes the part that truly makes bourbon, well, bourbon: aging in new charred oak barrels. The charring of the barrels caramelizes the sugars in the wood, creating a rich array of flavors that the bourbon will absorb as it ages.

The aging process is where time and environment play crucial roles. It matures differently based on variations in temperature, humidity, and barometric pressure. This is why the exact same brand can taste different from year to year or even barrel to barrel.

During aging, it undergoes a process known as the “angel’s share,” where some of the liquid evaporates through the barrel, leaving behind a higher concentration of flavors.


After aging, master distillers test it to determine if it’s ready for bottling. This involves tasting (a tough job, but someone has to do it!) and scientific analysis to ensure the bourbon meets the distillery’s standards.

Finally, it is filtered, diluted with water to bring it to the desired proof, and then bottled. And voila! From mash to bottle, that’s the science of it.

FAQs about the Science of Bourbon

Is It Only Produced in Kentucky?

While Kentucky is renowned for bourbon production, it can legally be made anywhere in the United States.

Can It Go Bad?

It doesn’t spoil, but its flavor can change over time. Proper storage is essential to maintain quality.

What’s the Difference Between Bourbon and Whiskey?

All bourbon is whiskey, but not all whiskey is bourbon. Bourbon has specific production requirements that set it apart.

How Long Does It Need to Age?

To be called straight bourbon, it must be aged for at least two years. However, many high-quality brands age longer for enhanced flavor.

Is There a Proper Way for Tasting?

Yes, sipping involves taking small sips, allowing the flavors to coat your palate. Adding a few drops of water can enhance the tasting experience.

Can I Mix Any Type into Cocktails?

While personal preference plays a role, it’s recommended to use mid-range types for cocktails to balance flavor and cost.

In the end, it is not just an alcoholic beverage; it’s a testament to the intricate balance of science and art. Each step in its creation, from the selection of grains to the aging process, involves careful scientific control and a bit of luck from Mother Nature. So, the next time you enjoy a glass, take a moment to appreciate the fascinating science that went into its creation.

At Bad Tom Smith, in addition to our craft beers, we also offer a wide array of bourbons in our taproom. From fan favorites like Bulleit to Woodford Reserve, to hard-to-find bottles like Eagle Rare and Buffalo Trace, to Bad Tom’s own Breathitt County and Cheating the Gallows, we have the best one for everyone’s taste. Visit our Cincinnati taproom to try ours today!