What Is Bourbon Whiskey?

Bourbon whiskey is America's native spirit. It's a tightly regulated product that must be produced in the United States and has a few distinct characteristics. By far, bourbon is the most popular style of American whiskey and it's among the best-loved styles of whiskey worldwide.

The world of bourbon is complex and the brands are numerous. In order to fully appreciate bourbon, it's good to understand what defines this particular whiskey, what goes into distilling it, and how that relates to the whiskey in your glass.

Location

The laws governing bourbon production begin with where it can be produced. Though most people associate it with Kentucky, where the majority of bourbon is made, it can legally be distilled anywhere within the U.S.

Kentucky has long been the "home" of bourbon because of the state's natural resources. From the area's limestone base and hard water to the fertile soil that's perfect for corn, and the ideal climate conditions for barrel aging, it's the perfect place to make great bourbon. The first bourbons were produced there and there is even a Bourbon County, though most bourbon today is made around Louisville, Frankfurt, and Bardstown.

In the growing bourbon market, you can now find impressive bourbons from the states of Washington and New York. Small craft distilleries in Colorado, Florida, Illinois, Iowa, Michigan, Pennsylvania, Tennessee, Texas, Virginia, and Wyoming produce bourbon as well.

Mashbill

Bourbon must be made with a minimum of 51 percent corn, which gives the whiskey a noticeable sweetness. Most bourbons, however, are made with over 70 percent corn.

Grains like barley, wheat, and rye make up the rest of the mash bill (the mix of fermented grains that are distilled into whiskey). Rye provides a spicy note to bourbon whereas wheat provides a softer, sweeter note.

It is often in the non-corn portion of the mash bill where bourbons become distinct from one another. For instance, Maker's Mark includes red winter wheat, which is why it tastes softer and richer than most bourbons. On the flip side, Bulleit Bourbon's mashbill includes 17 percent rye (high for bourbon standards), making it one of the spicier bourbons you'll find.

Distillation and Proof

Traditionally, bourbon is double distilled to ensure smoothness and quality, though that's not a requirement. Bourbon cannot, however, be distilled to more than 160 proof (80 percent alcohol by volume, or ABV) initially.

Bourbon must go into the barrel at no more than 125 proof (62.5 percent ABV). If the distillate is higher than that, it must be diluted with water before it goes into a barrel. 

Bourbon may not be bottled lower than 80 proof (40 percent ABV), though many are stronger than that. Some are bottled at cask strength (or barrel proof), meaning that they are not diluted with water between the barrel and the bottle.

Aging

By law, bourbon must be aged in new oak barrels. These barrels must be charred on the inside and most distilleries use a number four (or "alligator") char. Since bourbon distillers cannot legally reuse their barrels, they are often sold after the first use to age other liquors, including rum and tequila.

As to how long a bourbon must be aged, the law doesn't specify any amount of time. In theory, a distiller could age whiskey for just one day and be able to legally call it bourbon. However, most bourbons spend a few years in the barrel; four to seven years is the average. If you find a bottle of 10-year or older bourbon, it's likely a special release that also commands a higher price.

Straight Bourbon

Bourbon aged at least two years may use "straight bourbon" on the label as long as the age of the whiskey is specified. Bourbon that is aged at least four years does not need to list an age statement for "straight bourbon," however. Therefore, if you see a bottle labeled "straight bourbon" without an indication of its age, it is at least four years old.

Bottled-In-Bond Bourbon

You will also find bourbon labels that say "Bottled-In-Bond." It's a complicated designation, but essentially the whiskey is the product of one distillery from one distilling season. These whiskeys must be aged at least four years and bottled at a minimum of 100 proof (50 percent ABV).

Flavor Profile

By law, no flavorings or color additives may be added to bourbon. Bourbon's general flavor profile can be characterized as having big vanilla, oak, and caramel notes. This makes it a perfect whiskey for mixing into cocktails as well as enjoying straight or on the rocks.

Flavored "Bourbon"

If bourbon cannot include extra flavors, why are some bourbons flavored? Technically, the apple, cinnamon, and other flavored "bourbons" are whiskey liqueurs. They are not a true bourbon and cannot legally be labeled as one.

For example, Jim Beam Apple may start out like any other bourbon from the distillery, but once that apple flavoring is added (often along with sweeteners), it must then be labeled as a "whiskey liqueur." Many brands continue to place "bourbon" on the label, though you'll notice that it's no longer prominent or "straight" bourbon. Often, you'll see a carefully worded statement like, "Apple-flavored liqueur with a bourbon whiskey base."

Cocktails

Bourbon is a popular foundation for many classic and modern cocktails. It's so versatile that you will enjoy it in almost any drink recipe that does not call for a specific style of whiskey.

There are a number of famous bourbon cocktails that should be on every whiskey lover's radar. These drinks are ideal when you're exploring brands as well because they do not overpower the whiskey. Instead, they let it shine with just a little flavor enhancement that will show off any bourbon's finer points.

The old-fashioned, for instance, is a nearly naked sipper of bourbon, with nothing more than sugar, bitters, and a couple of fruits mixed in. Likewise, the John Collins offers a taller, more refreshing way to enjoy a whiskey while the Manhattan is whiskey's answer to the martini and perfect for dinner. If you want to see how a bourbon stands up against tart citrus flavors, there's the whiskey sour. And, of course, any bourbon should be able to hold its own in the mint julep.