Short answer
When a raw material comes from a new supplier, or a new lot arrives from the same one, treat it as a potential change to every formula that uses it. Record the supplier, product code and lot on receipt; compare the new material side by side with retained stock of the old; request the new supplier's documents; recheck allergen and restricted-constituent data; and, if the difference is noticeable, re-evaluate the affected formulas before the next production batch. Keep the decision in writing.
Why the same material can change
- Naturals vary with species, origin, climate, harvest and extraction. Two lots of the same essential oil from the same supplier can differ; oils from different suppliers often do.
- Synthetics differ by grade. Isomer ratios, impurities and stabilizers differ between manufacturers, and some materials are sold in several grades.
- Suppliers reformulate. A compound or base bought from a supplier may be changed by them, sometimes with a new code, sometimes without.
- Documentation changes. A new supplier's allergen or restricted-constituent data may differ, and that can change your compliance calculations even if the smell does not.
What to record on receipt
- Supplier, the supplier's product name and code.
- Lot or batch number, date received, quantity.
- Certificate of analysis for the lot, if provided.
- Whether this is a change of supplier, of grade, or a new lot of the same product.
A change of supplier or grade is normally a new material record, so that formulas say exactly which product they use. A new lot of the same product is the same record with a new lot entry. Fragrance material names and CAS numbers explains why identity has to be this precise.
The same comparison, in a shorter form, belongs on every delivery, not only on a change of supplier; see checking raw materials when they arrive.
Comparing old and new
Keep a small retained sample of each lot you use in production — a few grams in a well-filled, sealed, labeled vial, stored cold and dark. When a new lot or supplier arrives:
- Dilute old and new identically (for example at 10% in the same solvent).
- Smell them side by side on blotters, at the opening and after an hour or more.
- If they differ, make the formulas that depend on the material most heavily with each, and compare those too.
- Record what you found and the decision: accept, accept with formula adjustment, or reject.
Comparing in a formula matters: a small difference in a material at 2% may vanish, while the same difference at 25% is obvious. How to make the same perfume twice covers the wider question of batch consistency.
Documents to request
From a new supplier, ask for the safety data sheet, the specification, an IFRA certificate or statement of conformity where relevant, and an allergen statement. Compare them with what you had: a different CAS number, a different allergen profile or a different IFRA limit is a change you must carry into your calculations. Safety data sheets, specifications and CoAs explains what each document tells you.
When a formula must change
If the new material smells different enough to matter, adjust the formula — and make the adjustment a new formula version, not a silent edit. Record that the change was driven by a material change, so later readers know why. If the material is part of a product you sell, the change may also affect the safety assessment and the label (for example, if allergen levels change). How to adjust and refine a perfume formula describes how to make controlled changes.
A supplier change log
A simple log is enough for a small lab:
| Date | Material | Change | Compared with | Result | Formulas affected |
|---|---|---|---|---|---|
| 2026-03-04 | Bergamot oil FCF | New lot, same supplier | Retained sample, prior lot | Slightly greener; accepted | None changed |
| 2026-05-19 | Vetiver oil | New supplier and origin | Retained sample; two formulas remade | Smokier; new material record; formula adjusted | Formula 12, v7 → v8 |
For how supplier and lot records fit into the material record as a whole, see the raw material documentation guide.
Frequently asked questions
Do I need to re-test every new lot?
For materials that matter to products you sell, a quick side-by-side comparison with a retained sample is worth doing every time. For minor materials in trials, use judgement.
How long should I keep retained samples?
At least as long as products made with that lot may be on the market, and long enough to compare with the next lot. Keep them cold and dark so they change as little as possible.
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.