My Team Accidentally Mixed Raw Materials From Two Suppliers — How Can Better Storage Labels and Lot Tracking Prevent This at Larger Production Volumes?

First, deal with the stock that is already mixed

Before you redesign anything, contain the problem you have. Stop using the mixed material at once, move it to your hold area and label it clearly as mixed and not for production. Then work out three things: what exactly was mixed, how much of each, and which batches have already used it.

The first question matters because not all mix-ups are equal. Two lots of the same wax from the same supplier tipped into one bin is a traceability problem. Two different waxes from two suppliers in one bin is a formulation problem, because the blend may melt, set, adhere and hold fragrance differently from either wax alone. A fragrance oil topped up with a same-named oil from another supplier is the most serious of all, since two oils with the same name can smell quite different.

Be honest with yourself about the cost. Writing off a few kilograms of mixed wax hurts. Shipping 200 candles that behave unpredictably hurts more, and for longer.

Why materials get mixed as volume grows

At small scale, mix-ups are rare because there are only one or two bags of anything open. As volume grows, several things change at once: more deliveries, more suppliers, more people handling stock and more decanting into working containers. Almost every mix-up traces back to a working container that lost the identity of what was in it.

Notice that none of these causes is a careless person. They are gaps in the system that any person will eventually fall through on a busy day. That is good news, because systems are easier to fix than people.

Labels that survive decanting

A label has one job: to let anyone, at any time, identify exactly what is in a container without asking. It fails if it can be separated from the material, if it is incomplete, or if it stays on the original pack while the material moves into a bin.

The rule that makes labels work at scale is simple: when material moves, the label moves with it. A decanted bin of wax gets a complete label copied from the pack, not a word scrawled in marker. If you cannot be bothered to label a container, the material should not go into it.

For supplier markings, record whatever is printed on the pack. If nothing is printed, rely on your own receiving code. For CSI deliveries, ask on WhatsApp (+91 7397976926) what batch details can be shared, and add the answer to the receiving record rather than guessing a lot structure.

Storage layout for more than one supplier

Physical separation catches what labels miss. Organise storage by material first and supplier second: all container wax together, then within that area one clearly marked zone per supplier and product. Put a shelf sign above each zone, so a pack placed in the wrong zone looks wrong from across the room.

At the melting station, allow one open lot per material. If a new lot is needed before the old one is finished, the old one is either used up, sealed and returned to its zone, or moved to leftovers with a label. Two open packs of the same material at one station is the moment a mix-up becomes likely.

Keep scoops, jugs and stirrers attached to one material where you can. A scoop moved from one wax bin to another carries a little of each; for wax that is minor, but a pitcher or stirrer moved between fragrance oils can carry scent from one batch into the next. Disposable bamboo stirring sticks remove that question entirely for the scenting step.

Lot tracking at the moment of use

Labels and layout protect stock on the shelf. Lot tracking protects the batch. The critical point is the moment material leaves storage for the melter, because that is where the wrong container gets picked.

Give each batch a short pick list that names the material code and lot code for every component. The person picking reads the label aloud against the pick list; a second person, or the same person at the melter, checks it again before anything is weighed. Then both codes go onto the batch sheet. It takes seconds per material and closes the gap that caused most mix-ups.

Add one more habit: record each withdrawal against the lot in your stock register. When the register says a lot should have 4 kg left and the bin holds 7 kg, something has been added that should not have been. A register that is checked weekly catches a mix-up days after it happens instead of months later.

When the switch is deliberate

Sometimes two suppliers are used on purpose, for example to cover a shortage. Treat the second supplier's material as a different material, not a second lot of the same one. It gets its own internal code, its own zone and its own approval test with your formula before it touches an approved product. Sharing one internal code between two suppliers is how a planned substitution turns into an accidental mix.

As volume grows, the same system scales without change: more zones, more labels, the same rules. What must not change is that every container, every pick and every batch sheet names the lot. When your team can answer the question which lot is in that bin? by reading rather than remembering, mixing two suppliers by accident becomes very hard to do.

Where this page fits

CSI already has guides that cover parts of this question. This page takes the production-floor angle; these go deeper on the rest:

Three things to buy for this job

Frequently asked questions