This year, whiskey was projected to outsell vodka for the first time in almost a decade. With the craft cocktail resurgence in full swing, it’s not hard to see why—many of those classic recipes call for bourbon or rye. Outside of cocktails, straight whiskey has developed a devoted following whose members are willing to camp out in the elements for new ultra-premium releases.
For many American whiskey fans, the spirit is appealing because it’s American made and home-grown. In fact, in 1964, Congress declared that bourbon specifically was America’s Native Spirit.
American whiskey, which includes bourbon, is also one of the most variable spirits out there. Every barrel of whiskey is slightly different from the ones that came before it. As a result, small production runs can vary greatly from bottle to bottle. For larger producers, consistency is maintained by blending whiskey from many barrels. On top of those distinctions, you have different varieties within the American Whiskey category. Bourbon, rye, Tennessee whiskey, single malt…keeping all that brown liquor straight can be confusing, so we’re going detail the differences between two of the most popular forms of American Whiskey: bourbon and Tennessee whiskey.
Under American law, whiskey is an alcoholic beverage distilled from fermented grains. It may be distilled up to 190 proof (95 percent alcohol by volume, or ABV), and must be stored in oak and bottled at no less than 80 proof. The law doesn’t specify if the oak containers need to be new and it doesn’t put a minimum on the amount of time the whiskey must spend in a barrel (those specifications will come later, with bourbon and Tennessee whiskey).
So, rye whiskey, malt whiskey, bourbon, Tennessee whiskey, wheat whiskey and corn whiskey all fit the definition of “American whiskeys.” Within the overarching American whiskey category, producers have been getting creative with the development of their whiskey’s taste profile. Some small producers have even been experimenting with nontraditional grains like millet and quinoa to create novel products.
Five factors affect how whiskey will turn out: its water source, grain recipe, fermentation process, distillation process, and maturation in oak, says Chris Morris, master distiller at Woodford Reserve. Around Kentucky, the water is “especially full of micronutrients, which feed the yeast and result in the light floral flavors in the whiskey.”
Many distillers in Kentucky and Tennessee cite limestone-rich water sources as being one of the most important parts of their whiskey’s flavor. Since combining the water and grain base—also known as a mash bill—is the first step in distillation, these ingredients shape much of the whiskey’s taste profile before it’s aged.
Needless to say, the quality of the grain will partially determine the quality of the resulting whiskey. The most common grains used for whiskey production are rye, malted barley and corn. Each grain adds different qualities to a spirit’s taste: rye will typically add spiciness, pepper, and a darker flavor. Malted barley gives a malty roundness, while corn adds sweetness, creaminess, and popcorn-y flavor.
To begin the fermentation process, the water and grain are combined in a mash tub, and then transferred to a fermenter. Here, a combination of yeast and naturally occurring enzymes in the malted barley begins the fermentation process. Because the yeast (and how long the solution is allowed to ferment) impacts the sugar content of the final product, changing the strain that’s used can completely change the final product’s taste.
The end result of this process is a thin alcoholic liquid known as distiller’s beer. This liquid is then transferred into a still. Most distillers use copper stills because of a specific reaction between the distillate and the metal in the still that removes unwanted sulfur and sulfide compounds.
Finally, the whiskey’s time in an oak barrel is what makes up 100 percent of its color and, depending on who you’re talking to, 50-80 percent of its flavor. These barrels are stored in warehouses called rickhouses that aren’t temperature regulated. During the summer, the liquid in the barrels expands through the char and into the wood of the barrel. In winter, the liquid contracts and brings with it all of the taste and aroma compounds imparted by the wood.
Subcategories of American whiskey such as bourbon and Tennessee whiskey are restrictions on name. Each of these is legally regulated, but at different governmental levels. Bourbon is legally defined at the federal level, while Tennessee whiskey is a matter of state law.
To be called bourbon, the whiskey must be produced within the U.S. and meet the American legal requirements for whiskey. If it’s produced within the state of Kentucky, it can be labeled as Kentucky bourbon. The mash bill must be at least 51% corn, and no flavoring or coloring may be added. The last item has one exception: water may be added to cut the whiskey’s strength to enter the barrel and/or bottle.
Further, bourbon must be distilled at 160 proof or less, and must enter the barrel at 125 proof or less. The barrels used to age it must be made from new charred American white oak. To be labeled straight bourbon whiskey, it must be aged for longer than two years. Why “straight” came to mean “aged for more than two years” is still unknown.
Believe it or not, Tennessee whiskey and bourbon have almost identical requirements. In fact, most Tennessee whiskeys meet the criteria for bourbon. The main difference in production is that, sometime after distillation, Tennessee whiskey must be filtered through sugar maple charcoal. Though most producers filter directly after distillation, the law doesn’t (currently) specify when it must be done.
Parts of the state’s legal definition are hotly contested. The two major contenders, George Dickel and Jack Daniel’s, are each fighting a different requirement. With the current shortage of barrels after a poor harvest, Jack Daniels’ has argued that the new barrel restriction is untoward. George Dickel, on the other hand, ages much of its whiskey in Kentucky, which is obviously outside the Tennessee state lines, thereby blurring the lines of what constitutes production.
One of the most enduring questions in bar culture is the best way to taste and drink whiskey. It’s simple, says Jim Beam Master Distiller Fred Noe. “You should drink it any damn way you please.”