My New Wax Batch Gives More Wet Spots Even Though the Jar, Fragrance and Pouring Process Are Unchanged — Should I Compare Retained Wax From the Previous Lot?

Yes — and check the jars while you are at it

Wet spots are the patches on the side of a container candle where the wax has let go of the glass. From outside they look like damp or darker areas. They happen when the wax shrinks as it cools and sets, and loses contact with the glass in places. Soy wax is particularly prone to it, and it is usually cosmetic: the candle burns the same. But customers notice it, and a sudden increase after a new lot of wax is a reasonable thing to investigate at goods-in.

So yes, compare retained wax from the previous lot. It is the only fair way to tell whether the new wax adheres differently. But before you run that comparison, look honestly at the word "unchanged" in your title. The jar model, the fragrance and the pouring steps may be unchanged. Are the actual jars from the same delivery as before? Are they being washed, dried and stored the same way? Is the curing room the same temperature at night as it was a month ago? Wet spots respond to all of those, and a comparison that only varies the wax will still be misleading if a new box of glass arrived the same week.

That gives you a sensible order: quarantine the new wax lot, check what else changed, then run a side-by-side comparison with retained old-lot wax in jars that are genuinely identical.

Five minutes on what else changed

Wet spots are influenced by the glass surface, the temperature difference between hot wax and cool jar, how quickly the candle cools, temperature swings during cure and storage, and handling. Before blaming the wax, walk through the list below and write the answers on the lot record.

If one of those answers is yes, you have a second candidate cause, and the comparison below needs to account for it. If every answer is no, the wax lot becomes the leading suspect, and a retained-sample comparison will confirm or clear it.

The side-by-side comparison, set up properly

The comparison works only if the wax lot is the single difference between the two sets of candles. Everything else comes from the same source, is handled the same way and sits in the same place.

That last step is optional but useful. Wet spots often appear or grow after a temperature swing, because wax and glass expand and contract at different rates. Moving all the test jars, both lots together, into a cooler space overnight and re-scoring them is a gentle stress test. If one lot develops noticeably more wet spots under the same swing, that is meaningful evidence.

Worked example: twenty jars and a grading scale

Suppose your product is the 150 g clear apothecary jar with a golden lid, which costs ₹1,888.00 for a pack of 20, or ₹1,888.00 ÷ 20 = ₹94.40 each. You pour ten jars from the retained old lot and ten from the new lot, one full pack. At 8% on total candle weight, each 150 g candle holds 150 × 0.08 = 12 g of oil and 150 − 12 = 138 g of wax, so the test uses 20 × 138 = 2,760 g of wax, 1,380 g from each lot.

Score each jar on a scale you set before looking, for example: 0 — no wet spots; 1 — one or two small patches; 2 — patches covering roughly a quarter of the visible wall; 3 — larger areas or a band around the jar. These bands are a suggested starting point; adjust them to what your customers actually notice. Add up the scores for each lot at each check point.

Say the old lot totals 4 across its ten jars on day 7, and the new lot totals 17, with the gap widening after the cool night. That is a clear, repeatable difference under identical conditions, and it points at the wax. If instead both lots total 12 or 13, the wax is not the cause; something in jars, cleaning, room or season changed for both. The same twenty jars answer the question either way, and good jars can still be used as your own reference candles afterwards.

The goods-in decision on wet spots

Most wet-spot investigations end in one of three places. Accept the new lot when its scores match the old lot's, and move your attention to jars, cleaning, cooling and the curing room. Conditional release when the new lot is slightly worse but still within what you would sell, perhaps directing it first to frosted or coloured jars, and keep scoring finished stock from the first production run. Quarantine when the new lot is clearly and repeatably worse under identical conditions, and take your scores, photos of both sets together, the invoice number and the date received to the supplier. For CSI that is WhatsApp on +91 7397976926; CSI does not publish adhesion data or per-lot tolerances for its wax, so your comparison is the evidence, and you should record the reply.

Reject a lot on wet spots alone only if your products depend on perfect clear-glass appearance and no reasonable process adjustment brings the new lot back. And if the comparison clears the new wax, say so on the record plainly. The next person who sees wet spots will want to know that the wax has already been tested, so they look at the glass and the room instead. If the new lot is the cause, send it back as a question whoever supplied it — including us — rather than quietly mixing it into the old lot where the wet spots will turn up in every batch.

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