Beginner perfumer · 96
I was comparing hours that cannot be compared — and half the '400 hours' in my own map were measured diluted
· 13 min read
The substantivity field reads 'N hours at M%', and I had only ever read the first half. Of the 2,027 records with a substantivity figure, 165 (8.1%) were not measured neat: 83 at 20%, 58 at 10%, and a handful at 1%, 0.1% and 0.05%. There are two distinct reasons and the data separates them — the 20% tier is 84.3% solids and resins (you cannot put a crystal on a blotter) but only 13.3% at the highest strength rank, while the 10% and 1% tiers run above 60% at rank 3. And 334 records read exactly 400 hours, of which 80 were measured at a dilution. Going back to my own palette map: of the 18 rows quoting a specific 400-hour figure, 9 came from diluted measurements. I have corrected all three language versions.
About a 4 minute read.
The substantivity field's full string looks like this:
400 hour(s) at 20.00 % in dipropylene glycol
I had only ever read the number in front.
Writing up furaneol last time I noticed its substantivity was stated at 20% rather than 100%, and explained why (it is a solid; there is no neat material to put on a blotter). Only then did it occur to me to go back and ask how many records look like that.
165
Of the 2,027 records with a substantivity figure:
| Measured at | Records |
|---|---|
| 100% | 1,754 |
| 20% | 83 |
| 10% | 58 |
| 1% | 12 |
| 50% | 5 |
| 0.1% | 4 |
| 3% | 2 |
| 0.05% | 1 |
165 records below 100%, or 8.1%. (A further 116 state no concentration at all.)
And these are not obscure records — vanillin (193 suppliers), l-menthol (114), raspberry ketone (112), maltol (107), nootkatone (104), strawberry furanone (101) are all in the 20% tier.
Two different reasons to dilute
I assumed dilution meant "too strong." It does not. There are two reasons, and the data separates them.
| Concentration | Records | Solid or resin | Share at rank 3 |
|---|---|---|---|
| 50% | 5 | 100.0% | 60.0% |
| 20% | 83 | 84.3% | 13.3% |
| 10% | 58 | 53.4% | 62.5% |
| 1% | 12 | 41.7% | 66.7% |
| 0.1% | 4 | 50.0% | 50.0% |
(For contrast: among the 1,754 measured at 100%, only 11.2% are solids or resins.)
The 20% tier is dilution for physical form — 84.3% solids and resins, but only 13.3% at the top strength rank. Vanillin, maltol, frankincense resinoid, oakmoss absolute, labdanum. They are diluted not because they are strong but because you cannot spread a crystal on a blotter.
The 10% and 1% tiers are dilution for strength — over 60% at rank 3.
One "not 100%", two completely different meanings.
And the 400-hour figure is a problem
The maximum substantivity in the database is 901 hours, but 334 records read exactly 400 — 16.5% of them all. That is plainly a ceiling, not a measured distribution.
Of those 334:
| Records | |
|---|---|
| Measured at 100% | 202 |
| Measured at a lower concentration | 80 (56 at 20%, 16 at 10%) |
| No concentration stated | 52 |
A quarter of the "400 hours" values were measured diluted.
Lasting 400 hours in a 20% solution is not the same as lasting 400 hours neat. The first has a fifth of the material and lasts as long, which is the stronger result. But there is no way to convert between them from this field, because substantivity is not linear in concentration.
My own map was wrong
I maintain a starter palette map for this series — one row per material, one column of which is substantivity.
I went back and checked. Of the 18 rows quoting a specific "400 hours", 9 came from diluted measurements.
| Material | What the map said | What the database says |
|---|---|---|
| Tonalide (AHTN) | Long (>400 h) | @10% DPG |
| sotolon | Long (>400 h) | @3% PG |
| Amber naphthofuran (Cetalox) | Long (>400 h) | @10% DPG |
| para-cresol | Long (400 h) | @10% DPG |
| 2-acetyl pyrazine | Long (400 h) | @10% DPG |
| BHT | Long (400 h) | @20% DPG |
| ethyl maltol | Long (360 h) | @20% |
| phenethyl salicylate | Long (232 h) | @20% DPG |
| IPM | Solvent (400 h) | no concentration stated |
(Two rows — musk xylol and castoreum absolute — I had written correctly all along, as "400 h at 20% in DPG." So I knew it needed stating, and simply did not do it consistently.)
All three language versions are now corrected to the "400 h at 10% DPG" form.
The check turned up one more error along the way: the lavandin row links to grosso (#21892, whose substantivity field is empty) while quoting 216 hours from lavandin oil (#21881). Writing that article last round, I mixed fields across three records of one family. The map now names the source.
In practice
- When you see an hour figure, look for the concentration after the
@. A number without one cannot be compared to anything. - 20% usually means it is a solid or a resin, not that it is especially strong.
- 10% and below usually does mean strong.
- Do not rank two 400-hour values against each other. That is this field's ceiling, not a measured limit.
This article is a correction, not a discovery. Last time I praised the evaluation concentration field for being exactly what it claims — and the substantivity field carries the same concentration marker, which I went a hundred-odd articles without reading.
What this doesn't establish
- "Solid or resin" is judged from the appearance string and a melting point above 25 °C, which is an approximation; most resins carry no melting point at all.
- Strength rank coverage is incomplete, so those percentages are shares among records that have a rank, not among all.
- The 0.1% and 0.05% tiers hold four records and one. Far too small to lean on.
- I cannot convert a 20% 400-hour value into a 100% equivalent. The relationship is not linear and I have no model.
- "334 records at exactly 400 hours means a ceiling" is inferred from the distribution's shape; the database documents no measurement limit.
- I corrected only the map. I did not re-check every article body that quotes an hour figure this round — that work is not finished.