Approving a sample is not the same as receiving the order. Production paste is made in a larger batch, in a different vessel, on a different day, filled on a different line and sealed with a different lot of tubes. Some of those differences are acceptable and some are not, and the only way to tell them apart is to compare the delivered batch against a reference both sides agreed on. This guide sets out what to compare, how to record it, and where a visual comparison stops being useful.
It is a comparison framework, not a claim about how much any batch will vary. Every tolerance in it is a value your team agrees with the supplier before production starts.
1. The reference has to be more than a photograph
A tube photograph, a marketing image or a sample someone kept in a drawer cannot serve as a reference, because nobody can prove it is the item that was approved. Two things make a reference usable: it is identified (reference number, approval date, who signed it) and it is retained under conditions that keep it stable, so it can still be compared months later.
Agree in writing which physical sample is the retained reference, where each side keeps its copy, and how it is stored. Our sample evaluation checklist covers documenting the approval itself; this article starts after that approval exists. The generic manufacturing term for a retained reference is a golden sample, and the practice behind it is the same in any industry: one item both parties can point at.
2. Agree tolerances before you need them
A comparison without a tolerance turns every difference into a debate. Decide in advance which attributes may vary, by how much, and which attributes may not vary at all. Write it into the purchase order or the specification so it is part of the contract rather than a favour.
| Attribute | How it is judged | Tolerance to agree |
|---|---|---|
| Paste colour | Side-by-side against the reference, same lighting | Match within an agreed visual band |
| Paste texture and flow | Squeeze test on the same surface | No separation, no graininess beyond the reference |
| Flavour profile | Blind tasting by the agreed panel | Acceptable to the panel against the reference |
| Fill weight | Scale reading per unit | A stated range around the declared net content |
| Tube print | Artwork revision and print position | Exact revision; print within an agreed offset |
| Decorative elements | Foil, spot colour, embossing if applicable | Present as approved; stated deviation limit |
| Cap, valve, closure | Fit, colour, torque | Same component reference as the approved version |
3. Compare like for like
Most arguments about "the batch is different" come from comparing two things that were never comparable: a sample stored in an office compared with a carton that spent weeks in transit, or a paste photographed under warm light compared with one shot under daylight. Fix the conditions before you judge the result.
- Bring both items to the same temperature and let them stand for the same period.
- Photograph them in the same frame, same lighting, same angle, with a scale and the batch code visible.
- Compare units of the same net content and the same packaging format.
- Record the date of the comparison, not only the date the batch was produced.
4. Record the comparison, unit by unit
A conclusion such as "acceptable" is not usable later. Log what was measured, on which units, with the batch code, so the record can support a decision in either direction.
| Field | Entry |
|---|---|
| Reference identity | Approved sample reference and approval date: ______ |
| Batch identity | Production batch code and production date: ______ |
| Units compared | Number per SKU, drawn from which cartons: ______ |
| Conditions | Temperature, lighting, time standing: ______ |
| Findings per attribute | Within tolerance / outside tolerance, with a photograph reference: ______ |
| Decision | Release / rework / hold, and who decided: ______ |
5. Match the batch record to the shipped units
A visual comparison confirms what the goods look like; the batch record confirms how they were made. Ask for the production and filling records that cover the batch codes on the delivered cartons, the certificate of analysis for those batches, and the incoming-material references used. Our quality control guide explains why traceability sits at the centre of that documentation, and our pre-shipment inspection checklist covers how to verify the batch codes on the units themselves.
6. Decide what to do when a batch falls outside
Fix the remedy in advance, per attribute class, so the decision does not depend on who is more tired at the end of the week. The workable options are rework and re-inspection, replacement of the affected units, or documented acceptance with a stated concession. Record which attribute triggered it and keep the photographs attached to the decision.
7. Where a visual comparison stops
Comparing a batch against a retained sample establishes that it looks, feels and tastes consistent with the reference. It does not establish stability over shelf life, microbiological status, abrasive behaviour, active content, or compliance for your market. Those come from the specification, the test reports and the stability file, and they are confirmed through those documents rather than by eye. Treat the comparison as one input among several, not as the release decision on its own.
8. Next step
Send us the product reference, the destination market and the attributes you want tolerances for, and we will confirm which specification fields and batch records accompany the order. Send your requirements, or start with the sample evaluation checklist so the reference itself is properly documented.