Iso E Super: the material you have smelled a thousand times
In roughly half the perfumes in your cupboard. Invisible to a good share of noses. Famous for being sold, almost undiluted, as a perfume in its own right.
If you own more than five perfumes made after 1980, you own this material. It rarely announces itself and it is almost never the reason anyone buys a bottle. It is, nonetheless, one of the most quietly consequential things a perfumer can reach for.
What it smells like — and the awkward part
Cedar, but sanded smooth. Warm, dry, slightly ambery, with a soft velvet quality that is much easier to recognise than to describe. It does not smell like a tree. It smells like the space around one.
Now the awkward part: a substantial minority of people cannot smell it at all, or can smell it only faintly and only sometimes. This is a real and well-documented partial anosmia, and it has a practical consequence you must plan around. If you are one of those people, you will overdose it, because you will keep adding until you can smell it — and by then everyone else is in a fog of it.
What it actually does
Its usefulness is not its smell. It is what it does to everything around it.
- It adds space. Blends that felt flat and pressed-together open up. This is the effect perfumers mean by "volume", and it is hard to get any other way.
- It smooths edges. A sharp aldehyde or a shrill floral becomes wearable.
- It lasts. Sixteen to twenty-four hours on skin. It is holding the perfume down long after the interesting parts have gone.
- It is cheap. Among the least expensive things on a professional shelf, which is part of why it is everywhere.
How much to use
| Dose in the concentrate | What it does |
|---|---|
| 1–3% | Invisible. Smooths and extends, nobody names it. |
| 5–10% | The workhorse range. Adds warmth and space you can hear. |
| 15–25% | A stated character. The perfume is now partly about this. |
| 50%+ | The modern overdose. A whole commercial genre lives here. |
If you are starting: put it at 8% and change nothing else. Make the same formula with it and without it, label both, and smell them side by side the next morning. That comparison is the entire lesson.
The overdose, and the perfume that made it famous
In 2006 Geza Schön released Escentric Molecules Molecule 01, which is essentially this one material and very little else. It should not have worked. It sold extraordinarily, and it did something more interesting than sell: it made a general audience aware that a single synthetic could be a finished perfume, and it turned the anosmia into part of the story — a scent some people cannot smell on you, but others can, is a good deal more romantic than a chemical from a catalogue.
What it is not
It is not a fixative in the strict sense — it does not slow other materials down so much as outlast them. It is not a substitute for a real wood; put it next to sandalwood or vetiver and it is obviously thinner and less interesting on its own. And it is not free of consequence at any dose: it is restricted under the IFRA Standards, so the amount you may use depends on what the finished product is and where it goes on the body.
The material page in the Crafted Scent application carries its family and facets, its strength, how long it lasts, its IFRA position and its CAS number — and the bench checks your dose against the standard for the category you choose, as you build.
Open the library →If you buy one bottle this month
Buy this one. It is inexpensive, it keeps essentially forever, it improves most things you will make in your first year, and it teaches you something no reading can: what a perfumer means when they say a blend needs more room.