By Rob Gray, Ph.D.

Experienced cigar smokers often remark that the flavors in a cigar change dramatically when smoke is blown out through the nose instead of the normal practice of releasing it through the mouth. In fact, Christian Eiroa, president of Camacho Cigars has made the following comment: “Unless you have blown smoke out through your nose while smoking a cigar, you have never really tasted the cigar.” Does this technique really change the flavors you get while smoking a cigar and if so, why? 

To address these questions we must first look at the basic sensations produced during cigar smoking. When one takes a draw on a cigar two primary senses will be stimulated: gustation (taste) and olfaction (smell). These two senses combine to produce “flavor”.  Note that the sense of touch is also stimulated by the texture of the smoke (i.e., “mouth feel”) and/or via pain receptors in the mouth and nasal cavity, but we will save that for a future article. The routes of olfactory and gustatory stimulation are shown in the figure below:

Gustation refers to the sensations that arise from the stimulation of taste buds and taste receptor cells found on the tongue and throughout the mouth. Olfaction refers to the sensation that arises from the stimulation of olfactory neurons located in the nose, specifically the olfactory bulb (shown in yellow in the figure). Particles in the air can reach the olfactory bulb through two different pathways. 

1. Orthonasal Olfaction - Sensations arising from aromas traveling through the nostrils, to the olfactory bulb.  This is what we typically mean by “smelling”.
   

2. Retronasal Olfaction - Sensations arising from aromas that travel “in through the back door,” or through the back of the throat into the nasal cavity.  The primary purpose of Retronasal Olfaction is to act as a last minute warning system in case you are about to swallow something harmful.
   

As illustrated by the thin line in the figure above, normally the number of aroma particles reaching the olfactory bulb via Retronasal Olfaction is much, much smaller than the amount via Orthonasal Olfaction and in many cases there may no molecules transmitted at all. Aroma particles transmitted through Retronasal Olfaction have a smaller channel to move through and must travel a greater distance (which increases the likelihood they will dissipate before reaching the olfactory nerves). However, by forcing the smoke up through the nasal cavity and expelling it through the nose, the number of aroma particles reaching the olfactory nerves via Retronasal Olfaction will be dramatically increased. The two different methods of expelling smoke are illustrated below.

To blow cigar smoke out through your nose you first need to close your mouth and draw the smoke into your throat as if you were going to swallow/inhale it. You next need to close your throat and push the smoke out through your nose as if you were making a snorting sound. Developing this breathing technique usually takes a lot of practice! It helps if you blow out most of the smoke in your mouth before closing your mouth and attempting to open up the back of your throat to blow the remaining smoke out through your nose.

Differences Between Orthonasal and Retronasal Olfaction

At this point a novice cigar smoker may be wondering: “why should I put the effort into learning how to blow smoke out my nose when it just leads to the same effect (aroma particles hitting the olfactory neurons) as pulling the smoke in through my nose by sniffing”?  In other words, aren’t Orthonasal Olfaction and Retronasal Olfaction just two different methods that have the same result?  As it turns out there are several important differences between these two types of olfaction that could dramatically affect the overall flavor of a cigar. 

First and foremost, is the difference in the composition of the aroma particles that arrive at the olfactory receptors. When a cigar smoker takes in air via Orthonasal Olfaction he/she is taking in both the aroma particles in the cigar smoke and aroma particles from other objects in the surrounding environment (for example, the cologne they are wearing, scents from flowers planted around a patio, or the body odors of other smokers). Conversely, during Retronasal Olfaction only the odor molecules drawn into the mouth in the cigar smoke reach the olfactory receptors. Thus, Retronasal Olfaction can be thought of as a more pure form of olfaction. This is why some cigar smokers make the analogy that expelling smoke through your mouth produces flavors like “taking a sip from a mixed drink” while expelling smoke through the nose is like “doing a shot of straight whiskey”.

A second difference is where the source of the olfactory stimulation is perceived to have come from. In laboratory experiments it is possible to isolate the two different types of olfaction by using tubes placed in the mouth and nasal cavity with an endoscope. Using this device, aroma particles can be sent into the nasal cavity either through the nose or the throat. Results from these experiments show that Orthonasal Olfaction triggers the perception that the source of the smell is located in the outside environment whereas Retronasal Olfaction causes the perception that the particles causing the aroma are in the mouth. Since we more readily combine our perceptions of retronasal aromas with our sense of taste, sensations produced by Retronasal Olfaction are often misperceived as being part of taste. For example, when we say a food tastes “spicy” or “fruity” these are not actually sensations that can be detected by our taste buds (which are only sensitive to sweet, sour, salty, and bitter), but are more likely the sensations we get from Retronasal Olfaction. In terms of cigar smoking this would suggest that when an aroma triggers the sensation of “leather” it is more likely to be treated as part of the flavor of the cigar (as opposed to some object in the smoking environment like a leather chair) when it is sensed retronasally. This is likely another reason why cigar smokers report that certain flavors are intensified when the smoke is expelled through the nose.

Just like those “secret men’s clubs” you see in movies where the bouncer slides open the window and asks for the secret password, cigar smoking has a secret “back door” only available to the initiated: Retronasal Olfaction. And once this door is opened the joint is jumping inside! Exhaling smoke through the nose can open up a whole new world of pleasurable flavors and aromas to the cigar smoker that are far more intense and rich. So, if you haven’t found it yet, keep looking for cigar smoking’s secret back entrance---a straight shot of flavor is waiting on the bar for you!

References:

Halpern, B. P. (2004). Retronasal and orthonasal smelling. ChemoSense, 6, 1-7.

Small, D.M., Gerber, J. C., Mak, Y. E., Hummel T (2005). Differential neural responses evoked by orthonasal versus retronasal odorant perception in humans. Neuron, 47, 593-605.

Rob Gray is Stogie Fresh’s resident “Cigar Science Guy.” He is an educator, researcher and writer. Rob conducts research in Human Factors Psychology at Arizona State University.

Rob is a regular contributor to the Stogie Fresh Cigar Journal.