How Do I Create an Incoming QC Specification for Candle Wax Covering Appearance, Odour, Melting Behaviour, Hardness, Finished Appearance, Fragrance Compatibility and Burn Performance?

What a specification is, and is not

Most makers who have been buying wax for a while already have habits: they look at the colour, smell a melted sample, maybe pour a test candle. A specification writes those habits down in a form that removes judgement from the parts that should not depend on it. For each parameter it answers four questions. What exactly are we checking? How do we check it? What result passes? How often do we check?

It is not a supplier certificate, and it is not a promise from the supplier. It is your internal standard for accepting a delivery into production. That distinction matters because most wax suppliers, CSI among them, do not publish lot-by-lot tolerances, colour specifications or certificates of analysis. A specification that demands figures the supplier never offered will either be ignored or will fail every delivery. A specification written against your own approved reference lot works with the information you actually have.

One page per wax grade is enough. If you use two grades, such as a container soy and a pillar soy, write two pages, because their criteria and burn checks differ.

The header: what you know before testing

The header records the context that makes the criteria meaningful. Keep it factual: only what the supplier states, and only what you have verified.

The seven parameters

The table below is a worked specification for CSI 468 in a container candle. The criteria and tolerances are suggested starting points to validate against your own records, not standards and not CSI policy.

Notice that every criterion refers back to the reference. That is deliberate. It means the specification stays valid even though you have no published tolerance to lean on, and it means a delivery is judged against the lot you know works in your product, not against a general idea of what soy wax should be like.

Writing criteria two people would apply the same way

A criterion fails if two careful people could read it differently. Looks fine is not a criterion; no visible difference in shade beside the reference on white paper in daylight is. Name the light, the background, the sample size and the comparison every time. For sensory checks, name the number of judges and require them to score before discussing.

Where you add a number, say where it came from. The 2°C and 10% figures in the example are starting points chosen to be loose enough to pass normal variation and tight enough to flag a real shift. After a year of records you will know whether they were right: if deliveries you later regretted all sat inside the band, tighten it; if good lots keep failing, loosen it in the next version.

Frequency tiers and a worked cost

Running every check on every delivery wastes time on deliveries that match. Tiering puts the cheap, fast checks first and saves the expensive ones for when they are needed. Tier A runs on every delivery and takes about half an hour. Tier B runs when a delivery is a new lot, or when Tier A flags a difference. Tier C runs when Tier B flags a difference, when you change anything in the formula, and on a schedule you choose, such as once a quarter.

Worked example: the Tier C check uses the reference formula of a 200 g candle in a clear salsa jar at 10% of total candle weight with Juicy Orange, whose page states soy use at 8–10%. Each candle takes 20 g of oil and 180 g of wax. Two reference candles and two new-lot candles make one Tier C run.

Set that yearly figure against one 25 kg delivery of CSI 468, which costs 2 × ₹6,370.00 + ₹3,185.00 = ₹15,925.00 before any oil or jars. The scheduled checks cost less than a third of a single delivery's wax, and they are the only part of the specification that tells you how the wax behaves in a burning candle.

Decision rules and keeping the document alive

End the specification with the rules that turn results into a status. A simple set: accept when all checks at the required tier pass; conditional release when a difference is confirmed but a recorded, lot-specific adjustment passes its own burn check; quarantine while any required check is incomplete or a supplier reply is pending; reject when a difference is confirmed, repeated and cannot be accommodated. Rejection applies whoever supplied the wax, including us.

A specification is only as good as its last revision. Review it whenever a problem reaches production that it should have caught, whenever you change grade, supplier or reference formula, and at a fixed interval you choose. Record each change with a version number, so a delivery from last spring can be judged against the version that applied then.

Where this page fits

CSI already has guides that cover parts of this question. This page covers the goods-in check for the question above; these go deeper on the rest:

Three things to buy for this job

Frequently asked questions