Basic smelling techniques are essential, and several viewpoints are culled here from the writings of industry pioneers Paul Jelinek, Edmond Roudnitska, and Stephen V. Dowthwaite. This summary provides fast practical advice. Enjoy! -LGV

1) The Environment
The act of smelling first starts in an appropriate environment, one that is as free as possible from abnormal ambient influences.
Optimum Environment for Smelling:
A Separate Room (with the following characteristics):
  • Well ventilated.
  • Strictly void of strong smelling samples and lab projects.
  • Normal room temperature.
  • Normal humidity.
  • Quiet /peaceful environment.
Undesirable Environments and Environmental Factors:
  • Smelly laboratory.
  • Production area.
  • Kitchen.
  • Rest room/bathroom.
  • High ambient temperatures.
  • High humidity.
  • High air pollution (or background odor).
  • Distracting (noisy, high-traffic, visually displeasing, etc.).
You are part of the Smelling Environment too!
  • Do not wear strong fragrances
  • Avoid a smelling session right after eating strong aromatic foods (onions, garlic, coffee, curry, etc.)
  • Avoid contaminating your hands, clothes and hair with samples. Tie your hair back if it is long.
  • Careful not to contaminate your nose by touching it with the smelling strip!
2) Material Samples
  • Use dilute solutions (to prevent odor overload and fatigue).
  • When you need to smell materials in undiluted form (neat) and to prevent olfactory overload and fatigue:
  • Minimize sample size; Dip the blotters in shallow (not deep) increments.
  • Minimize exposure; Limit to several brief inhalations.
  • Use appropriate solvents, i.e. - Alcohol for perfumery.
  • Use the final diluents “mixture” in your smelling sample, as each diluent will affect the odor performance of a perfume material.
  • Do not smell undissolved crystalline materials (the smell will be imprecise because of trace surface impurities. You might inhale actual crystals and deaden your sense of smell for a very, very long time).
  • Do not sniff at an open bottle directly (it will deaden the sense of smell for a prolonged time).
3) Smelling Strip & Blotter Recommendations
Common blotter recommendations:
  • Standardize using the same brand and stock of blotters (to avoid changes in smell from manufacturing differences and trace elements)
  • 13cm to 15cm.
  • 0.5cm to 1cm width.
  • Unsized (not treated or bleached).
  • Roudnitska:
    • 18cm length.
    • 1cm wide.
    • Folded with a groove (to prevent bending).
    • Tapered (to fit small bottles, and reduces material consumption).
    • Paper grade 180gm/sq cm.
  • Jelinek:
    • Minimum 10cm.
    • Thin blotters (allows different smelling phases to be recognized due to less tenacious holding of volatile materials).
    • Thick blotters (for presentation, as it holds the composition better than a thin blotter)
  • Dowthwaite:
    • Chromatography Paper (its thinner and has special characteristics).
    • Tapered.
    • Bend the smelling tip 3cm from the end (so you can easier coordinate your hands, and to help prevent the smell of your hand from contaminating the sample).

4) The Act of Smelling
The nose quickly adapts to unchanging smells, so time is short to fix an impression!
  • Smell some known samples from your lab in the same category you wish to identify to help refresh and reacquaint your memory.
  • Concentrate, your mind is really doing the smelling!
  • Be relaxed and comfortable.
  • Arrange samples from weak to strong (to offset olfactory fatigue).
  • Dip strips to a depth of 0.5cm.
  • Keep the strip 1cm-2cm perpendicular to the nostrils.
  • Close eyes to prevent visual distractions.
  • Use short shallow inhalations. Sniff-Evaluate—Sniff-Evaluate. Use short brief inhalations to experience the smell, move it away from the nose, then use your memory to hold the odor and evaluate. The first sniff will give the clearest impression, subsequent sniffs will blur.
  • Inhale through the mouth by holding it 1cm away from the lips to experience the odor differently by introducing taste sensations. Exhale back up past the throat and through the nose.
  • With a weak smelling sample, warm the sample by breathing gently out your nose onto the strip. The warm breath will warm the sample and increase its evaporation and activity.
  • Pose a series of “yes” or “no” questions to cycle through until an identification is made. (i.e. - Is it aliphatic? No, then is it citrus? No, then is it…).
  • Keep a database and write prolific notes of your immediate odor impressions. You are forced to think and smell with awareness when you do this, and it will help to recall the smell in the future. You will also be able to search and find the characteristics later.
    • Write with lucidity in your expression of the odor
  • Have rest intervals (for your nose to recover)
    • Go outside for fresh air between series of smelling sessions.
    • Stimulating deep breathing and circulation helps clear the nose. It has been suggested to run up and down a flight of steps!
Perfumery Practice and Principals, Calkin and Jellinek
How do you smell?, Stephen V. Dowthwaite