Shelf life and storage

The smell tells you nothing. The chemistry decides.

Ask how long an aroma material keeps and the useful answer is not about the plant it came from or the note it plays in a formula. It is about which class of molecule dominates it, because that is what decides how fast it reacts with the oxygen in the bottle.

This is why a rule of thumb by odor family is worthless. A woody material can be a sesquiterpenol that keeps for the better part of a decade, or a synthetic aldehyde that is tired inside a year. They sit next to each other on the shelf and in the pyramid, and they have nothing in common that matters here.

How long each class actually lasts

One class is not on the chart because it does not belong on it. A solvent in a closed bottle does not autoxidize the way a terpene does, and no published limit applies; the sensible interval there is a housekeeping one, which is to smell it before it carries another dilution. And where a material's chemistry is not established, no figure is derived at all, because a plausible guess about how long something stays safe is worse than an admission that nobody knows.

Cool storage doubles all of it, and this has been measured

The working rule is that room-temperature life is half of cool-storage life, and that warm climates are worse still. It is not a hedge; the mechanism has been measured directly.

The practical consequences follow directly. Keep what you can cool and dark. Decant into a smaller bottle as one empties, so the headspace of air above the liquid stays small. Close bottles properly and promptly rather than leaving a row of them open through a session. Buy the fast-oxidizing materials in quantities you will actually use inside their life, which for citrus means small and often rather than economically large.

An oxidized material is a safety question

This is the part that turns storage from housekeeping into compliance. The oxidation products of terpenes are considerably more sensitizing than the terpenes themselves. An oil that has gone over is not simply flat and disappointing; it is more likely to cause a reaction than the same oil was when it arrived.

That is why several IFRA Standards attach a specification to a material rather than only a concentration limit, and why a peroxide value appears in them at all. A specification is a statement about the bottle on your shelf, not about the formula on your screen, so a material can be comfortably inside its restriction and still fail its Standard because it has aged. It is the one kind of non-compliance that arrives without anybody changing anything.

Fixed oils fail differently and are worth naming separately: they go rancid rather than losing their terpenes, and the test that settles it is the peroxide value, which the European Pharmacopoeia holds to not more than 10 milliequivalents of oxygen per kilogram for vegetable fatty oils.

Period after opening, which is a different question

Everything above is about your raw materials on your shelf. The date on the carton is about the finished product in somebody else's hands, and the two are not the same question.

The EU Cosmetics Regulation requires a date of minimum durability, unless the product keeps for more than thirty months, in which case it carries a period after opening instead: the open jar symbol with a number and the letter M. That is a statement that the product remains safe for that many months once the customer has opened it, and like every other statement on a label it has to be one you can support.

What supports it is stability work on the finished product rather than arithmetic on your materials, and it is one of the things a safety assessor will ask about. A perfume at a high alcohol content is generally a stable thing; an oil-based or water-containing product is a different proposition, and preservation becomes a question the moment water is present.

What to write down

The date a bottle arrived and the date it was first opened, because the second is what the clock actually runs from. The lot, so a supplier telling you two years from now that a lot was off specification is a question you can answer. And where a material went: which dilutions were made from it, and which batches those dilutions reached.

None of that is interesting until the day it is the only thing that matters, which is the day somebody asks about one bottle that left your bench three years ago.

How Orris Bench handles this

A material carries its chemistry class as a fact of its own, kept deliberately separate from its odor family, and the shelf life is derived from that: the cool figure, and half of it for a bottle kept at room temperature. Where the class has not been established, no shelf life is derived and none is shown, because an invented date on a safety-relevant question is worse than a blank one.

Lots carry their own dates, so the clock runs from the bottle rather than from the material in the abstract, and a dilution knows the lot it was made from. That is the same chain the batch record uses, followed in the other direction: from a bottle back to what went into it, or from a lot forward to everywhere it ended up.

Sources

The figures by chemistry class are those the application uses, each taken from published guidance: Robert Tisserand on the citrus, conifer and lemongrass band and on the general two to three year figure, together with his instruction to halve it for oils that are not refrigerated; Aromatics International (Karen Williams, 2020) for the class-by-class ranges. The lemon oil measurement is Sawamura and others, International Journal of Aromatherapy, 2004. The peroxide limit for vegetable fatty oils is the European Pharmacopoeia general monograph. The period after opening requirement is Article 19 of Regulation (EC) No 1223/2009. This page is written for people who make fragrances and it is not legal advice; the stability of your own finished product is a question for the person who assesses it.