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Learn · Part One — Learning to smell · Lesson 3 of 9

How to smell something three times in three minutes

One long sniff tells you less than three short ones. The reason lies in how olfactory receptors work.

There is a mistake almost everyone makes at the start: breathing in deeply and holding it, in the belief that this will catch more.

The opposite is true.

Why smelling longer is worse

Olfactory receptors adapt very quickly. After about ten to twenty seconds of continuous exposure to a smell, the signal sent to the brain drops sharply. This is olfactory adaptation, and it is why you cannot smell your own home while a guest who has just walked in smells it at once.

Breathing in deeply and holding it is therefore the fastest way to blind your own nose.

How to do it properly

Three short sniffs, each about a second long, a few seconds apart. The way a dog sniffs — no coincidence; it is the optimal way to use this system.

Keep your distance. With strong samples such as medicated balm or clove, at least a hand’s span. Bringing it close only saturates the nose, and you lose the samples after it too.

Reset your nose between samples by smelling the crook of your own elbow for a few seconds. The smell of your skin is one your nervous system has fully adapted to, so it works like a reset button. This works better than smelling coffee beans — the coffee trick is popular in perfume shops, but the evidence for it is rather weak.

Three points in time

With a liquid sample on a smelling strip, smell at three fixed times: immediately, after half an hour, and after four hours. Write three words each time.

Those three sets of words are a map of the sample’s notes. The first time you catch the lightest molecules — the citrus group, the green group. The second is the body. The third is only the heaviest molecules, the woody and resinous group.

If you have a bottle of essential oil with an analysis, sort the components by rising boiling point and set your three sets of words beside the list. They will match, and that is the moment the analysis stops being a technical sheet of paper.

Four things to avoid

Don’t smell more than five samples in one session. Beyond that number everything starts to sound the same and you are wasting samples.

Don’t smell when you have a cold or have just eaten hot, spicy food. The nasal lining changes and the results cannot be compared with other sessions.

Don’t read descriptions before smelling. Vocabulary is very suggestive, and you will find exactly what someone else wrote. Smell first, write three words, then read.

Don’t correct your first note. It is rough and clumsy, and precisely because of that it is yours.

Further reading for this part

A shared list for the whole of Part One — Learning to smell, not a note for every sentence. We state what each source was used for.

  1. Asifa Majid and Niclas Burenhult, 2014. Odors are expressible in language, as long as you speak the right one A study of the Jahai of the Malay Peninsula, a group with an abstract smell vocabulary. It underpins the central argument of Part One: the gap lies in vocabulary, not in the nose.
  2. Caroline Bushdid et al., 2014. Humans can discriminate more than 1 trillion olfactory stimuli The trillion figure is widely quoted. We cite it together with its critique, because Meister (2015) and Gerkin and Castro (2015) showed problems with how it was extrapolated. It is our example of how an attractive number can spread without anyone checking it.
  3. Những cây thuốc và vị thuốc Việt Nam A Vietnamese-language source for the species names, parts used and sensory descriptions of most of the medicinal plants in the dictionary. Where it and other literature disagree — as with garden mint — we give both.

One thing must be said plainly. We have not read every work above in the original; most of the knowledge comes through secondary literature and reviews. We say so rather than let the list suggest a depth of research we have not reached.

Last updated: September 2026