What Makes Bourbon… Bourbon? A Deep Dive into American Whiskey Laws

What Makes Bourbon… Bourbon? A Deep Dive into American Whiskey Laws

When you sip a glass of Left Bank Bourbon, you're not just enjoying a smooth, complex spirit—you're tasting a product steeped in strict standards, rich history, and uniquely American identity. But what exactly makes bourbon... bourbon? And why does it matter?

Let’s break down what sets bourbon apart from every other whiskey on the shelf—and why these rules protect the quality, flavor, and legacy of every bottle.

🥃 The Legal Definition of Bourbon

In 1964, the U.S. Congress officially declared bourbon “a distinctive product of the United States,” granting it legal protection both domestically and internationally. According to U.S. federal regulations, a spirit must meet the following criteria to be labeled bourbon:

✅ 1. It Must Be Made in the United States

Contrary to popular belief, bourbon doesn’t have to be made in Kentucky—but it must be made on U.S. soil. That said, about 95% of the world’s bourbon still comes from Kentucky, the spiritual (and literal) heartland of the industry.

✅ 2. It Must Be Made from At Least 51% Corn

Bourbon’s sweetness comes largely from its grain bill—specifically, a minimum of 51% corn. The remaining grains usually include malted barley, rye, or wheat, each contributing unique flavor notes.

✅ 3. It Must Be Aged in New, Charred Oak Barrels

This is one of bourbon’s signature traits. Used barrels or wine casks? Not allowed. Bourbon gets its amber color and rich vanilla-caramel notes from new American oak barrels, charred on the inside to perfection.

✅ 4. It Must Be Distilled to No More Than 160 Proof (80% ABV)

Distillers must keep the alcohol concentration under this limit to retain more flavor from the grains—unlike neutral spirits like vodka, which are distilled at a much higher proof.

✅ 5. It Must Enter the Barrel at No More Than 125 Proof (62.5% ABV)

Once distilled, the spirit must be proofed down with water before entering the barrel for aging. This helps ensure balance and prevents over-extraction from the oak.

✅ 6. It Must Be Bottled at 80 Proof or Higher

To carry the bourbon label, the final product must be bottled at a minimum of 80 proof (40% ABV), though many premium bourbons—including Left Bank—are bottled stronger for richer flavor.

✅ 7. It Cannot Contain Any Additives

No coloring, no flavoring, no blending allowed. True bourbon is pure—what you taste is the result of the grain, the barrel, the aging process, and nothing more.

🏷️ Straight Bourbon? Small Batch? Single Barrel?

• Straight Bourbon: Aged at least 2 years (and labeled as such if under 4), with no additives.

• Small Batch: Bourbon blended from a select number of barrels for unique character.

• Single Barrel: Each bottle comes from one individual barrel—unblended and distinct.

Left Bank Bourbon offers a range of expressions that highlight these classifications, each crafted with a nod to heritage and a taste for excellence.

📜 Why These Laws Matter

These standards aren't just red tape—they’re the reason bourbon has maintained its integrity and identity for generations. By protecting the process, we protect the product. That’s why Left Bank follows these rules to the letter, ensuring every sip you take is the real deal: bold, balanced, and unmistakably bourbon.

Raise a glass to tradition. Next time someone asks what makes bourbon bourbon, you'll know the answer—and you’ll have the perfect bottle to prove it.

Ready to taste the difference? Come try a pour of Left Bank and experience bourbon, done right.