My Customer Complains the Jar Became Extremely Hot Near the End — What Production Records Should I Check Before Deciding Whether It Is a Wick Problem?

The complaint, made precise

The situation, stated exactly: a customer reports that near the end of the candle the jar became extremely hot. You don't know yet how long they burned it, how much wax was left, where it stood or whether the flame was normal. You have a batch code (if you print one), the batch's records (if you keep them) and perhaps retained candles. You want to know what to check before deciding it's the wick, because changing a wick across your range is expensive and a wrong change can create new failures.

The worked example in this post, labelled: a batch of 50 candles, 200 g at 8% = 16 g Woody Oud + 184 g wax (load as a percentage of total weight), one Eco C2 wick each, the series default candle. The recipe for the batch is 10,000 g of finished mix: 800 g oil and 9,200 g wax. 2 candles were retained and 48 released for sale. Most candles from the batch have had no complaint, which is itself information: a design problem tends to show in every candle burned the same way.

The first 24 hours

Reply quickly, without arguing and without promising a cause. Thank them, ask them to stop using the candle, and ask these questions; each answer narrows the search:

Then check whether anyone else bought from the same batch, and whether any other complaint mentions it. One complaint from a batch of 50 with nothing else reported is a reason to investigate, not yet a reason to recall; three from the same batch is a pattern.

The records to pull, in order

Pull them in this order: the cheap, fast checks first, the ones that need a burn last. Worked-example findings are in the last column.

Three things in the example are flagged, and none of them proves anything on its own. The load was 8.73% instead of 8%: inside Woody Oud's stated "6-10%" and CSI 464's "up to 10%", but not what was approved, and higher loads of dense oils are commonly linked with more carbon on the wick (a tendency, not CSI data). The wick lot's neck measured 4 mm against 6 mm, so the flame may run lower before it stops; the published sibling my wick supplier changed the tab explains why a tab change alone justifies an end-of-life check. And the label printed no maximum session, so a customer burning for six hours wasn't told otherwise. Record 11 is the quiet one: if the configuration was approved without bottom-third readings, the design itself was never checked where the complaint happened, and the problems that only appear in the second half of a candle's life were never looked for.

Causes ranked, and the record that rules each in or out

The ranking is our judgement for a single complaint of a jar extremely hot near the end, with the glass intact. Signs are common observations; CSI publishes no end-of-life or heat data for any wick or jar.

Causes 1 and 2 come first because a single complaint against a batch with no others is most often about how one candle was burned. They're also the ones that most need careful wording: you're telling a customer something about their own use, so lead with the facts you measured on your retain, not with blame. Causes 3 to 5 are batch causes, and the records point straight at them. Cause 6 is the only one that justifies changing the wick across the range, and the only one where flame growth late in the jar (a flame that gets larger as the wax level drops) is the expected sign.

Reproduce it with a retain

Three arms. R: your 2 retained candles from the complaint batch. P: three fresh candles made exactly to the approved spec (8%, approved wick lot if you still have retained wicks from it, same jar). W: three fresh candles one CSI rung smaller (C2 → C1), poured only if R and P both run hot at the bottom. 8 candles at most; 6 re-pours need 96 g of oil and 1,104 g of wax.

About 10 days with daily sessions (worked example). If the complaint batch's oil lot is used up, say so in your report: arm P then tests the design with a different lot, which is still useful, but not the same question.

The decision path, and the rest of the batch

While you investigate, hold unsold candles from the batch rather than shipping more of a possible fault; holding stock costs storage, not reputation. If the retains reproduce the hot end, think about the 48 candles already sold: whether and how to contact buyers is your business judgement (this isn't legal advice), but the records you've just pulled are what let you scope it to one batch instead of your whole range.

The CSI buy list, retain costs and production

Argued against our own interest: most hot-end complaints end in a label change and a better batch sheet, not a wick order, and you may not need anything from us at all. CSI's wick range is also short: no sized, tabbed wick between C1 and C2, nothing tabbed smaller than C1, one wooden wick width, no stated neck heights, and no published lot data. If a design fix needs a finer step, we'll say so on WhatsApp rather than sell you the nearest rung.

What a retain policy costs

Retains are what made this investigation possible, so price them. One 200 g retained candle at CSI prices is ₹93.36 of wax (184 g of CSI 464 at the 10 kg price), ₹72.50 of Woody Oud (16 g at the 1 kg price) and ₹9.44 for the wick: ₹175.30 of materials, plus your jar. Two per batch of 50 (4.0% of the batch) is ₹350.60, or ₹7.30 on each of the 48 saleable candles. Keep them labelled with the batch code, out of light and heat, for at least as long as you expect customers to be burning that batch (your judgement). Three spare wicks per lot add ₹28.32 for C2.

The step to production quantity

Only if arm W won, and only after three of three. Worked example, labelled: four batches of 50 is 200 candles a month; plus 2% is 204 wicks, so 2 × 100 + 20 = 220 C1 for ₹1,298.00 (if C2 stays, ₹2,076.80), the same per wick at any pack. Holders: 10 packs (₹1,180.00) hold a whole 50-candle pour and are reused. Reorder point = daily use × your lead time + safety stock; CSI publishes no lead times, so ask on WhatsApp.

What to buy, and what to skip

Four items for the records and the reproduction, chosen on page statements, price and stock on 7 October 2026. CSI publishes no end-of-life, heat or lot data, so nothing is ranked on performance.

Skip for now: a new wick size across the range before the reproduction decides; the Pen Thermometer (₹354.00) as a glass gauge (it's for wax temperature on your batch sheet, not glass; CSI lists no non-contact thermometer); wooden wicks as a fix (one width, a different system to test from the top); and any 500-pack before three candles pass.

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