How to tell if a perfume formula is finished

A perfume formula is finished when the last three changes made it different but not better, when it matches the sentence you wrote for it at every time mark, and when a full rest and a day on skin produced no new complaint. Finished is a decision backed by trials, not a feeling on a good afternoon.

What are the stop rules?

Four rules, and a formula should pass all of them.

• Every line has a job you can name. Read the formula top to bottom and say what each line does. A line with no answer comes out, and if the formula does not miss it, it was finished without it.
• Removing any line changes the idea. This is the mirror of the first rule. Try it: a version with each questionable line at zero. If the blind pair cannot tell, the line goes.
• The sentence holds at every mark. Ten minutes, one hour, four hours and the next morning should all smell like the brief. A perfume that is the idea for an hour and then something else is not finished; it has a base problem.
• The last three changes did not improve it. Different is not better. When three consecutive single-change versions lose or tie against their parent in a blind pair, the formula has found its shape.

Why do versions matter more than my taste today?

Because your nose on any one day is not a stable instrument. It tires, it adapts to whatever it smelled last, and it prefers what you worked on. A formula judged on one afternoon is judged by whoever you were that afternoon.

Versions fix this. Each one records what changed from its parent and what the blind pair said, so a decision is a line of evidence rather than a mood. When you want to know whether the formula is done, you do not smell it and wonder; you read the last five versions. If they wander, a change up, then the same change back, then up again, the formula is not finished, you are circling. If they converge, and the notes say "tie" three times, it is.

Keep the losing versions. A branch you abandoned is the fastest answer to "what if we tried more musk" six weeks later: you did, and here is what happened.

What are the last three trials?

When the stop rules pass on strips, three more trials stand between the formula and a bottle.

1. The full rest. Make a batch at the real concentration and let it macerate for the full period, two to four months by strength. Smell it at day seven, at the halfway point and at the end. If a complaint appears at the halfway point that was not on the fresh strip, the formula is not finished.
2. A day on skin. After the rest, wear it for a full day and write down the marks the same way you did on strips. Skin is warmer and wetter than paper, and bases in particular behave differently on it.
3. A stranger's nose. Give a strip and the sentence to someone who did not make it and ask whether the strip is the sentence. Do not ask whether they like it. Liking is not the question; matching is.

Pass all three and the formula is finished. Fail one and you have a version to make, and the loop starts again from a known parent.

A worked example

A fougère that has been through eleven versions: Lavender Essential Oil 22 parts, Geraniol 6, Coumarin 12, Bergamot Essential Oil 15, Vetiver Essential Oil 8, Tonka Bean CO2 Extract 5, Iso E Super 20, Ethylene Brassylate 12. The brief was "a barber's shop with the door open onto a garden".

Versions nine, ten and eleven each moved one line: coumarin up to 15 (tie at every mark), geraniol down to 4 (lost at one hour, the garden went), vetiver up to 10 (tie, slightly muddier at four hours). Three single changes, no win. Every line has a job: lavender and geraniol are the garden, coumarin and tonka are the barber, bergamot opens the door, vetiver and Iso E Super are the floor, the musk carries it to morning. Version eight is the candidate. It goes into a 40 gram batch at 18 percent, rests three months, gets worn for a day, and goes on a strip in front of someone who has never heard the sentence. If they say "a barber's, but outside", it is finished.

What if it never feels finished?

Then the brief is probably wrong, not the formula. A sentence with two ideas in it produces a formula that can satisfy only one at a time, and every version trades one for the other. Split the brief into two perfumes and finish each. The other common cause is a nose that has stopped hearing the formula from too many days on it; two weeks away and a fresh strip usually settle whether it was ever unfinished.

PerfuMate's evolution tree shows each version beside its parent with the lines that changed, which is where the three-tie rule is read, and Compare puts two versions side by side with shared lines aligned. The maceration journal dates the final rest and its milestones, and the drydown chart with its confidence figure says what to expect at each mark before the strip does. The AI is handed the catalog and your shelf on every run and is never trained on them. See how the bench works.