The single highest-leverage habit in essential oil sourcing is to match three identifiers before you accept a drum: the purchase order line, the supplier’s Certificate of Analysis (COA) lot number, and the physical container label. If those three do not agree exactly, stop and quarantine the material—do not sample, blend, or repack it.
Most batch rejections are not from bad oil; they are from paperwork drift. A supplier issues a COA for lot L24-0715, the warehouse slaps a label reading L240715, and the buyer logs it under the PO item name only. Six months later, a customer asks for the COA and nobody can prove which drum it belongs to.
The Three-Point Lot Check
Before sampling, place the purchase order, COA, and physical drum label side by side. Confirm the lot number matches exactly—including dashes, spaces, and date format. Confirm the botanical name and country of origin match the PO. Confirm the net weight on the COA equals or exceeds the actual container weight. If any point fails, quarantine the drum and request a corrected COA or written lot clarification from the supplier. Do not accept verbal confirmation alone.
Retention Sample Routine
Once you accept a batch, pull a 15–30 ml retention sample into an amber glass vial. Label it with your internal lot code, supplier lot, date received, and COA reference. Store at 15–25°C away from light for the shelf life of the material plus 12 months. For citrus oils, a smaller 10–20 ml sample stored at 4–8°C can help reduce top-note fade, but a cool dark cabinet is acceptable for most oils.
Quick FAQ
What if the COA lot number and drum label differ by a hyphen? Treat it as a nonconformance until the supplier confirms in writing that both refer to the same batch. A single character mismatch can break your traceability chain.
How long should I keep COA files? Keep a read-only PDF tied to the internal lot number, plus the retention sample. For most essential oils, retain documentation for at least 3 years after the last shipment, or longer if your customer contract or regulatory standard requires it.
Can I pass a supplier’s COA to my buyer? In B2B, you may pass through the supplier COA if you have a signed agreement and the material is unchanged. Better practice is to issue your own conformity statement that references the original lot and COA number.
For more sourcing & formulation references, see https://aromakosmos.com
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