We asked Tom Johnson, the trainer at the Aroma Academy in the United States, to share some facts and insights about the nature of Aroma as it relates to the appreciation and enjoyment of Bourbon. Tom delivered with the following list that will blow your mind, clear up some common misconceptions, and even stop your palms from sweating next time someone asks what you’re “picking up” on the nose of your favorite Bourbon. Enjoy!
1The sense of smell is analog, not digital. It is a spectrum fading smoothly from one color to the next without any clearly delineated borders. While scientists estimate that human beings can differentiate more than 1 trillion different smells, for the sake of simplicity the brain sorts those different combinations into families of aromas. There’s a range of chemical mixes that may, technically, be differentiated, but your brain calls them all vanilla, saving distillers the chore of creating a flavor wheel with a trillion different options. 
2Human beings have about 6-10 million olfactory receptors in the nasal passages. That compares to more than 100 million for dogs.
3Women in general have about 40% more olfactory receptors than men.  The increased sensitivity and precision of the female nose is a big reason why women are rapidly moving up in the business of distilling, particularly in positions that require sensory assessment of spirits.
4Whatever you think you smell in whiskey is right. The brain associates certain sets and ratios of chemicals with experiences from your past. Peeling an orange, for example, releases a set of chemicals that your brain will forever associate with orange. But the brain makes other associations that can be much more personal. Certain sets of chemicals bring back the memory of a warm family kitchen, a fresh sea breeze, or even a beloved person. Those associations are every bit as valid as anything any self-important expert has to say. 
5Most of aromas you detect in whiskey are coincidences. There’s no caramel or clove or apple in whiskey. What you’re smelling is sets of chemicals formed during fermentation, distillation, and aging that remind your brain of smells. Unrelated to whiskey, but fun: the molecules floating around in space that are the residue of dying stars smell to astronauts like burned steak. 
6The estimates that 80-95% of “flavor” is really aroma aren’t supported by science. That doesn’t mean they’re wrong; it’s just that flavor is such a complicated thing, no one has figured out how to quantify it. It is, scientists (sort of) agree “a complex combination of the olfactory, gustatory and trigeminal sensations” – aroma, taste, and feeling. Without question, aroma is the most important component of flavor, but how important is the subject of vigorous debate. 
7Smell is the most sensitive sense. A healthy human nose can detect a skunk from only 0.000,000,000,000,071 of an ounce of spray. That’s’ the equivalent of less than a drop in an Olympic-size swimming pool. If you could see as acutely as that, you would be able to detect a candle at a distance of hundreds of miles. 
8Language and the sense of smell are disconnected. When you struggle for words to describe a familiar aroma, it’s because the olfaction process goes on in the right side of the brain and language is primarily in the left. 
9Cooked bacon is one of the most complicated everyday smells. It is made up of more than 1,000 different chemicals forming a pattern the brain instantly recognizes as breakfast. 
10The sense of smell helps run your body. The same type of olfactory receptor cells that tell you your whiskey is high in rye are used in other parts of the body to perform other duties. For example, receptors in the heart muscle appear to “sniff out” metabolic information that regulates the heartbeat. There are also olfactory receptors that identify and kill cancer cells. 
About the Author:
Tom Johnson is the trainer for the Aroma Academy in the United States. Aroma Academy teaches drinks professionals how to properly assess fine wine and spirits. Follow him on Twitter @AromaAcademyUS.