Short answer
Evaluate a perfume formula the same way every time: on labeled blotters and on skin, at set time points (for example the opening, 30 minutes, 2 hours, 6 hours and the next day), side by side with the previous version or a reference, after the trial has rested. Write down what you perceive in specific terms — what is strong, what is missing, how it changes — not just whether you like it. Consistent method is what makes one trial comparable with the next.
Prepare the trial properly
- Let it rest. Concentrates and diluted perfumes change in the days after mixing. Compare trials of similar age, and do not make decisions on a trial mixed an hour ago. See perfume maceration and aging.
- Evaluate in the final format. If it will be an alcohol spray at 18%, evaluate it at 18% in alcohol, not as neat concentrate.
- Label everything. Blotters, vials and skin sites need the version number. Unlabeled blotters are the most common reason evaluations are lost.
Blotters (smelling strips)
Blotters are the perfumer's main evaluation tool because they are consistent and comparable. Dip the tip to the same depth each time, label the other end with the version and time, and smell from a short distance rather than pressing the strip to your nose. Keep strips apart — on a stand or clip — so they do not contaminate each other, and keep them for later time points.
Blotters show the formula's structure and evolution clearly, but paper is not skin: it is neutral, cool and does not absorb or react the way skin does.
Skin
Skin shows how the perfume actually wears: warmth increases evaporation, and the drydown on skin can differ noticeably from the strip. Apply a measured amount (one spray, or a fixed number of drops of the diluted perfume) to a consistent place, and compare no more than two trials at a time — one on each arm. Skin varies between people, so for anything you will sell, evaluation by several people is worth the effort.
Time points
| Time | What you are judging |
|---|---|
| Opening (0–5 min) | First impression, top notes, alcohol, any harshness |
| 30 minutes | Transition into the heart; gaps after the top |
| 2 hours | The heart: character, balance, strength |
| 6 hours | Drydown: base materials, longevity, what remains |
| Next day (blotter) | Tenacity of the base; anything unpleasant left |
The same schedule for every trial is more important than the exact times. It is also the clearest way to see the structure described in top, middle and base notes.
Compare, don't just assess
Noses are much better at comparing than at judging in isolation. Always smell a new version side by side with the previous one, or with a reference — a target perfume, a previous approved version, or an accord. Ask specific questions: is the opening brighter? Is the heart fuller or thinner? Has something disappeared?
For important decisions, blind comparison helps. Ask someone to label two blotters A and B without telling you which is which, and record which you prefer and why before revealing them. It removes the bias toward the version you just worked hard on.
Managing your nose
- Evaluate in a well-ventilated room that does not smell of anything in particular.
- Take short breaks; olfactory fatigue sets in quickly with strong materials.
- Smell something neutral — many perfumers use their own skin — between samples.
- Avoid evaluating when you have a cold, or immediately after eating, smoking or wearing another fragrance.
- Evaluate at the same time of day where you can; your perception varies.
Recording what you smell
"Nice" is not a useful note. Useful notes describe what is perceived, where in time, and how it differs from the comparison:
- version, date, format and strength, and the trial's age;
- time point and medium (blotter or skin);
- what dominates, what is missing, what is out of place;
- comparison with the previous version: better, worse, different — in what way;
- a decision: what to change next, and why.
Over time, these notes are worth more than any single formula, because they record what each change did. Keep them with the formula version they describe — in a notebook (how to keep a perfume lab notebook) or attached to the formula in software. In RUŌOD Lab, each formula has its own working notes field alongside its version and status, and notes can also be kept as separate, searchable records.
From evaluation to the next version
An evaluation should end in a decision: change one thing, test a different strength, let it rest longer, or approve it. How to make that change in a controlled way is covered in how to adjust and refine a perfume formula. For the whole development cycle, see the perfume formulation guide.
A ready-made sheet with these fields is in the perfume evaluation sheet. When the question is whether two samples differ at all, a triangle test answers it more reliably than one person's impression.
Frequently asked questions
How many trials can I evaluate in one session?
Fewer than you think. For careful comparison, a handful of blotters at a time is plenty; beyond that, fatigue makes judgements unreliable.
Should I ask other people to smell my trials?
Yes, especially for anything you will sell. Give them specific questions and the same conditions each time, and record their responses separately from your own.
Written and reviewed by the RUŌOD Lab team. This article is general education about perfume formulation and record-keeping; it is not legal, regulatory or safety advice, and the examples are illustrations, not validated commercial formulas. How we write and check these guides.