Making Sense (and Scents) of Aroma Chemical Names

There are said to be 40,000 named odorous chemicals. To learn the odors of a good portion of these would take a lifetime. So here I will introduce a system that structures the understanding of the relationship of odors to one another and helps break down the problem of remembering a large number of chemical names and smells into a few logical steps. First, consider this quote from R. Harper et al.

Olfaction is undoubtedly a chemical sense; an odour is in all cases the end result of a process which is initiated by the interaction of volatile molecules (i.e. chemical substances) with the olfactory epithelium. The stimulus may, as in the case of the most common odours, such as from foods or perfumes, be a complex mixture of chemical species, or it may be essentially a single chemical substance such as ammonia. In addition the “odour” may be complicated by stimulation of pain or other receptors which are not located in the olfactory epithelium and which account for pungency, coolness and other non-olfactory sensations. These are nevertheless integrated with the true odour response to form an overall pattern which is recognised as a particular odour. However, excepting tumours, lesions or other interface with higher centres of the brain, including hallucinations, there is, to our knowledge, no case on record of an odour response, which cannot be explained as being initiated by the molecules of chemical substances. Hence, as odour perception is the result of, and only of, a chemical initiating stimulus, it is reasonable to attempt to classify odours in terms of known chemical structures.”

I will now introduce a system that helps classify odors of chemicals in such a way that will allow one to group and cross-index them according to structure and odor. When one sees the name of a chemical for the first time, one will already have a good idea of what that material will smell like. No, not precisely, but enough to know that if someone presents the completely wrong material, it will be obvious. Within a few hours of practice with the system, one should: 1) Have a good idea of what odor to expect from a named but previously unknown chemical; and 2) When looking for an elusive odor to complete a project, have a good idea of what chemical identities/structures to look for.

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