Popular Olfactory Theory and its Relationship to Accurate Test Results
Popular Olfactory Theory and its Relationship to Accurate Test Results
We seldom consider popular olfactory theory and its relationship to accurate evaluation and accurate test results. Our human sensory biology converts the data from molecular contact with a cilium into descriptive words. The process is both incredible and amazing. The process reveals the frailty and strengths of our olfactory and gustatory systems. As a result, we become aware of our limitations in nosing, tasting, and evaluation. Understanding them improves accurate test results. Olfactory theory has several schools of thought, however, lock and key is the accepted theory.
Basic Theory of Olfaction
Richard Axel and Linda B. Buck received the Nobel Prize in 2004 for their discoveries of odorant receptor function and organization of the olfactory system. Accordingly, this theory has become the present, popular mainstay of olfactory sensory research. It states that every olfactory receptor is a “lock” and every aroma is a “key.” Additionally, different olfactory receptors detect different families of aroma molecules. It’s the accepted olfactory theory.
When an aroma molecule attaches to a receptor cilium, the receptor sends the smell signal to the brain for recognition. Humans have at least 6 million receptors, some say much higher, 10-20 million. Nose receptors are finite; the first aroma molecule to reach the cilia occupies one until mucous flushes it away. Deeper investigations into olfactory theory are constantly undertaken.
How the Nose Processes the Molecular Contact
The mucus traps molecules in the epithelium layer. They find a cilium (hair) to which they connect. The celium sends a signal to the ORN. They are said to “bind” with the ORN. The olfactory nerve sends the signal to the brain for interpretation.
How the Brain Processes the Signal into Conscious Word Description
The above diagram is a signal flow chart for olfactory (green), taste (red) visceral processing (lavender and light blue) and mouthfeel (purple). Do we not definitely take our sensory for granted? The olfactory is actually the simplest process. The odor signal passes from the olfactory bulb through the olfactory nerve and finally arrives at the primary olfactory cortex. The brain interfaces with our memory of vocabulary and aromas and converts the signal into our conscious language. As an aside, we can see how important it is to establish a good, descriptive vocabulary which has a common ground and understanding between individuals. Communication on the same level is the hallmark of good spirits evaluation and makes a huge contribution to evaluation repeatability and accurate test results.
Ethanol is the Biggest Threat to Accurate Spirit Evaluation
We will limit the discussion to olfactory in this presentation. Remember that olfactory contributes 90% of the information which describes flavor (mouthfeel and taste are the remaining 10%. Since olfactory is the major component of flavor, and flavor evaluation of spirits is what we are all about, it is appropriate to discuss ethanol (at least 40% of a spirit by volume), its effects on the olfactory system, and its effect on accurate test results.
How Much Ethanol is there in Spirits?
A 40% ABV (alcohol by volume) spirit evaporates quickly into the atmosphere. Place two (the same shape) glasses one with 1⁄2 oz whisky and one with 1⁄2 oz water on the kitchen counter. After 24 hours the liquid level in the whisky glass is much lower or has disappeared entirely. This is due to the fact that alcohol evaporates first and quickest of any compound in a spirit. It evaporates first because it is a simple molecular shape, the smallest mass molecule of any in the spirit, has a lower surface tension, and a lower boiling point than water, which is almost 60% of the whisky. Ethanol evaporation is occurring while water molecules form hydrogen bonds with each other and are strongly polar.
This is science talk which means alcohol is significantly more volatile than water and evaporates much quicker than water (properties of ethanol and water are shown in the second diagram below).
Moreover, ethanol is the most abundant compound in all spirits, which are bottled at 40%+ ABV (alcohol by volume). Remembering why the nurse rubs your arm with an alcohol (methanol) pad before the needle will help place the sensory effect of ethanol in perspective, most think it’s because methanol and ethanol alcohols are antiseptics (sterilizers), which they most certainly are, but they are also anesthetic (numbing) to human olfactory neuron receptors whether they are on the skin, the tongue (pallet burn or pallet overload), or in the olfactory cavity. Your whisky or rum may have 40% alcohol, 59% water, and 1% other flavors, in its liquid existence, but the collected evaporation cloud of aromas that emanate from a pour of straight spirits at any given moment is more like 95% ethanol, 4% water, and 1% spirit character aroma compounds, due to the high volatility of ethanol.
Silent Ethanol Destroys Olfactory Without Warning
A high ethanol load quickly dulls olfactory receptors, as vaporized molecules rush to cilia before aroma compounds arrive. The nose is rendered “dumb.”
Clues to Olfactory Fatigue
Two general statements characterize this condition: ‘Everything smells the same’ and/or ‘I can’t smell anything.’ “Everything smells the same,” and/or “I can’t smell anything.” In the vast majority of cases, this is caused by anesthetic ethanol, and it occurs rapidly in spirits and wine. There are no warning signs and no way of knowing when anesthesia begins. The only cure is to stop sniffing to allow time for recovery. 70% recovery takes 3-4 minutes, and full recovery at least 7 minutes, as the mucous slowly replaces itself on the epithelium (which covers the cilia), washing away the previously attached aroma molecules.
Olfactory Recovery: The Fallacy of Reset Mechanisms
“Oh, that’s okay, I have my little saucer of coffee beans to sniff whenever I think I am losing my sense of smell.” Danger, Will Robinson! This is only true to those who believe it. Mythical and steeped in traditional yet erroneous thinking, it simply justifies continuing to smell, when symptoms of ethanol anesthesia begin to appear. In the final analysis, the only known procedure to repair ethanol anesthesia is recovery time. Again, the mucous layer must completely replace itself and wash away the molecules attached to the cilia. This myth has been around since the origin of perfumery (Egyptian dynasties?) and has no scientific or factual basis. Coffee beans are pretentious Tomfoolery as are the myths of smelling one’s skin or armpit to regress the nose to neutral. Total BS. All of it. Definitely, waiting is the only way.
Olfactory System Collapse: Fatigue
The major and frequent complaint of spirits and wine competition judges comes from “nose-blindness,” olfactory fatigue, or ethanol anesthesia. Smelling and tasting many samples in a relatively short period repeatedly exposes olfactory neurons to ethanol and they are anesthetized. There are many other contributors to ethanol anesthesia, such as methods of tasting, as well as glassware shape (to be discussed later). Regardless, the toll of ethanol anesthesia in a spirits judging competition is horrific to the competition’s credibility, and the judges, and monetarily damaging to the innocent entrants.
Olfactory Auto-compensation: The Role of Experiential Memory
What happens to an evaluation when olfactory ethanol anesthesia occurs? Other senses kick in to save the day and complete the task. Memories of past tastings rise to the forefront as a shopping list from which the evaluator may choose. Memory auto-compensation begs questions: “If this is a whisky, I should smell honey, caramel, and oak.” To compensate for a temporary loss of smell, the brain suggests a solution. It urges the evaluator to consider spirits from previous occasions to aid in solving the identification problem. The result is an evaluation of past experiences replacing the sample in the glass in front of the evaluator. See more science on the NEAT glass.
Scoring is Compromised by Olfactory Fatigue
Judges desperate to fill the trusted role of evaluator, affected by olfactory ethanol anesthesia, keep quiet to avoid detection and failure. They often write down an evaluation of what they want to find, or mimic and nod to others’ suggestions. Few admit to the problem, particularly when competition administrators depend on their reputation, expenses-paid input. Not a good thing for entrant or distiller. The entrant simply wants a fair chance for recognition and paid a $300–$500 entrant fee and sacrificed two bottles and the costs of safe shipping for each entry. Medals can be worth their weight in marketing gold.
When the evaluation is compromised, it’s impossible to know exactly where ethanol anesthesia first occurred. Perhaps the whole flight was compromised as well. Information regarding judging accuracy of the preceding flight also remains unknown.
Auto-compensation is Misleading
Be aware of the silent enemy and take precautions to preserve evaluation and enjoyment. Limiting olfactory exposure to ethanol is mandatory. Ignorance or denial of ethanol effects hurt your pocketbook and your appreciation of spirit quality.
Auto-compensation aids survival by reacting to a dangerous aroma. However, if ethanol anesthesia is the cause, it defeats the entire evaluation. Ethanol, our trusted and loved friend who occasionally lightens our burden and is a welcome source of elation and escape when used properly, becomes our sworn enemy when we evaluate spirits. An evaluator must develop a heightened and acute awareness that ignored and undetected ethanol aromas will destroy a spirit evaluation quickly and unnoticed.
Conclusions Regarding Ethanol
As a consumer, ratings aid selection of spirits. Relying on ratings means trusting the evaluator. Sources of ratings and tasting notes is high priority. Medals indicate quality, competitions may not use precautions to ensure accurate scores. Journal paper on the ethanol affect on aroma detection.
Ethanol Awareness
• Full enjoyment of straight spirits and wines is available to everyone. Maximum appreciation of both awaits those who understand and practice preventing the onset of olfactory ethanol anesthesia. See more in an independent research study.
• We will always encounter self-styled “experts” who profess to know more than those who use logic and science as an integral part of their lives. Stay away! Stay further away from those who claim to evaluate more than 5 spirits in a single sitting. They cannot possibly understand what they are doing, and this behavior is an indication that there are prurient interests at work behind the scenes. See more design information. Technical journal paper regarding the ethanol effects on evaluation.
Summary
Understanding the role of popular olfactory theory in our process of converting the characteristics of an aroma molecule to descriptive, conversational words is truly amazing. By modifying it with “popular” we understand that olfactory and sensory science is subject to change as new discoveries are made. Science puts us closer to understanding the mysteries of the universe, and it can go as deep as our own human bodies. A good, professional evaluator will know how the system works, its limitations and its wondrous abilities, and use it to the advantage of improving accurate test results. Ethanol is the focus of this independent study by Sensation Research.
