What's the Difference Between Whiskey and Bourbon?

"Whiskey is any distilled spirit derived from grain not distilled to 190 proof," Fletcher says. "Once you get to 190 [or higher] you're making a 'neutral' spirit, such as vodka." He also says that whiskey must be exposed to oak. "Typically, a barrel is used for aging the spirit." So that's it: Whiskey is a distilled spirit derived from grain, not distilled higher than 190 proof, exposed to oak. And that's that, right? Not quite.

"If you think about whisky, globally," Fletcher says, "you have Scotch whiskys, Irish, Japanese and Canadian. But it's when you get to American whiskeys you find the most stringent laws that define what you can put on a label that claim a type of American whiskey."

American whiskeys are legally defined and regulated by the Alcohol and Tobacco Tax and Trade Bureau. By law to be labeled as a straight American whiskey, it must be aged in new, charred-oak containers or barrels, and the grains that make up those whiskeys have to be a certain percentage. For example, straight American rye whiskey has to contain at least 51 percent rye and must be aged in new, charred-oak barrels/containers at least two years and be distilled in the same state.

Bourbon also has strict guidelines. It can be made in any state in the U.S., though Kentucky is most famous for it. It, too, is a straight American whiskey, but the mash has to have at least 51 percent corn in the recipe, and it must be aged in new, charred oak containers/barrels. "There are other technical specifications to the process," Fletcher says.

For instance, whisky (note spelling) outside of the U.S. can be distilled as high as 189 proof, but in the U.S. bourbon can't distilled any higher than 160 proof. "That retains more of the flavor of the grains from the fermentation process, the step before distillation," Fletcher explains. American bourbon also can't be added to the barrel for aging if it's already above 125 proof. Water is usually added to the final un-aged whiskey to bring it down to the desired proof. Some brands take it down as low as 114 proof before adding it to the barrels for aging, usually for at least four years or more.

You might have heard it said that all bourbon is whiskey but not all whiskey is bourbon, and that's why. Bourbon is a spirit, derived from at least 51 percent corn, not distilled higher than 160 proof and placed in new charred-oak barrels at 125 proof or below. It must be bottled at a minimum 80 proof.

Now, what's the difference between bourbon and Tennessee whiskey? One extra step. "Jack Daniel is a Tennessee whiskey and it qualifies 100 percent as a bourbon," says Fletcher.

To be a Tennessee whiskey the spirit must be made in Tennessee — it's geographically restricted. Next, it has to qualify as a bourbon whiskey. "That means it must follow the 51 percent corn minimum," says Fletcher, "the distillation maximum of 160 proof (we're actually well below that at 140 proof at Jack Daniel). We always have to age in a new, charred oak container/barrel and it has to go in at 125 proof or below. We hit all those criteria."

Finally, the Jack Daniel Distillery adds a final step referred to as charcoal mellowing. At Jack Daniel they make their own charcoal on the premises from maple wood burned to complete coal. The coal is packed tightly into a large vat, then the freshly distilled, un-aged whiskey (still clear at this point) is filtered through the charcoal.

"If you've ever used a water filter like a Brita, there's charcoal in it, but it doesn't flavor your water," Fletcher says. "The concept is similar. The whiskey goes in clear and comes out clear and then goes in the barrels to age." Fletcher says this expensive final step, which was once used by bourbon-makers in Kentucky, is a differentiator for Jack Daniel, and meaningful to their brand. "Even though our product does qualify as bourbon," he adds, "we prefer to be identified as a Tennessee whiskey."

The reason bourbons or whiskeys taste different from one another has to do with sourcing of the ingredients inside the bottle, not the label on the front. A spirit made from distilled corn will taste different from one made from distilled rye. After all, it's a different recipe.

And at Jack Daniel Distillery, for example, they inoculate their fermentation using a yeast strain that they can date back to Prohibition. "It's still grown fresh from the mother culture in our lab every day," Fletcher explains. "That yeast is a massive source of flavor for our whiskey and if we use a different yeast than the next distillery, that's a major flavor difference."

Kerri Richardson, president of the Bourbon Women's Association located in Louisville, Kentucky, says female bourbon drinkers frequently choose higher proof bourbon as their favorites, and she has medical and anecdotal data to back it up. Sensory studies done in the 1990s demonstrated that women have a genetic predisposition to picking up scents and flavors thanks to larger olfactory centers in the brain.

"When you have a very high proof whiskey, there's usually a lot of interesting things happening in that bottle and [women] really tend to go for that," she says. "We had a blind tasting a year ago of Heaven Hill [bourbon] products and I knew what would be in that lineup. I didn't know which was which, but I knew the one we would pick as our favorite — the highest proof — and I was right."