How Do I Diagnose an Oversized Candle Flame Using Wick Length, Wick Size, Melt-Pool Depth, Wax Consumption, Soot and Container Temperature?

The six measurements: what each can and cannot tell you

Each of the six measurements responds to more than one cause, which is why one alone misleads. A long wick makes the flame tall whatever its size. A draught makes soot whatever the wick. A heavy oil can mushroom a correctly sized wick. Only together, and only when you remove the burning variables in a second session, do they separate the four causes. The table is the reference for the rest of this page.

Two of the six need a reference. Consumption means nothing without a rate to compare with: use an approved candle in a similar jar, or, if you have none, the one-rung-down candle in the confirmation test. CSI publishes no grams-per-hour figures for any wick. Glass temperature needs your own limit; CSI lists no non-contact thermometer and publishes no glass-temperature limit, and the "Safe for hot pour up to 85°C" wording on our 150 g jar pages is a pour limit, not a burn rating. Flame height is deliberately not one of the six: it is the symptom you are diagnosing, and you log it on the sheet as the outcome. If you want the pass line for the flame itself, the impressive-versus-controlled criteria set it.

The recording sheet

One sheet per candle per session. The header records the conditions that can fake a result; the body records the six measurements and the flame itself. Fill it in at the time, not from memory at the end of the evening.

Limits and scores: 0, 1 or 2

Scoring makes six different units comparable. Every measurement gets 0 (within your limit), 1 (borderline, worth watching) or 2 (over your limit). The starting limits below are rules of thumb or in-house examples, labelled; change them to suit your range, but change them before the burn, and keep them the same for every candle you compare.

The percentages for consumption are an in-house example, not a standard; pick yours from how much variation you see between identical candles. If three candles of the same formula already differ by 10% between themselves, a 10% band will flag noise. The depth bands follow the common rule of thumb that a container pool of roughly 0.5–1 cm is a typical target and much deeper is a warning. There is deliberately no total score: the verdict comes from which measurements stay high, not how many points add up.

From scores to a verdict: the ranked causes

Here is the scoring rule. Score session 1 as found. Run session 2 trimmed to 5–6 mm in still air, with nothing else changed. If you suspect a draught, run a third session with the fan back on. Then read the pattern against the table. The ranking is our judgement of how often each cause explains an "oversized" flame, and it is also the cheapest order to rule them out.

Mixed patterns are common. The worked example below is a trim issue and an oversized wick: the trim removed some of the problem and the depth and consumption that remained are the wick. That is exactly why the second session matters. Formulation is a tendency, not CSI data: vanilla-rich, resinous and dark gourmand oils commonly build more carbon than light oils, and loads move wicks both ways (lavender fine, vanilla huge, bigger flame after lowering the load). If the glass is the high score and nothing else is, check centring and the lower third before anything: a drifting flame heats one wall (pool depth as the candle deepens covers the depth mechanism).

Where this sits in the cluster: individual symptoms each have their own page, from the hour-three growth hub to too large after a correct trim and wax disappearing too fast; this protocol is the common method underneath them. The wider wick-symptom tree across tunnelling and drowning is the systematic diagnosis capstone.

Worked example: one candle, two sessions

A 200 g candle at 8% (16 g oil + 184 g Luxury Soy Wax CSI 464) on an Eco C2 wick, in the reader's own jar, first third. The reader has an earlier approved candle in a similar jar that burns at 6.5 g an hour: that is the reference.

Reading it. The trim and the still air took wick length from 2 to 0 and soot from 2 to 1, and they straightened the flame. That part was how the candle was burned. What stayed: a pool still reaching about 2 cm, consumption still 40% over the reference (36.4 g in four hours against about 26.0 g), the glass still at the reader's limit, and a flame still climbing towards 5 cm. That is the oversized-wick signature, and it is in the top third, where the candle is coolest. At 9.1 g an hour the 180 g above a 1 cm floor would also run out in about 19.8 hours against 27.7 for the reference rate. Verdict: trim issue plus oversized wick; confirm one rung down. The fan side's dark patch in session 1 is a note for the care label, not the cause.

Confirming the verdict: test plan and approval rule

For the oversized-wick verdict, the confirmation uses the series' default test candle, labelled: 200 g at 8% = 16 g fragrance + 184 g wax (load as a percentage of total weight), in your jar. Three arms: your current wick, one CSI rung down, and a C1 pair in case the single smaller wick tunnels. Three candles each, 9 in all, scored on the same sheet every session.

Buying for the protocol, and the step to production

Argued against our own interest: if your verdict is a trim issue or a draught, the right purchase is a ₹177.00 cutter or nothing, and a clear line on your care label. Only the oversized-wick and formulation verdicts lead to wicks. And measuring tools you already own (a 1 g kitchen scale, your own non-contact thermometer, a bamboo skewer) are as good as ours for this.

CSI's sized, tabbed wicks are three rungs: C1 → C2 → Cotton Braided, so the confirmation step is always Cotton Braided → C2, C2 → C1, or a C2 pair → a C1 pair. There is no sized, tabbed wick between C1 and C2 or between C2 and Cotton Braided, no smaller sized, tabbed wick than C1, and one wooden-wick listing with no widths. If your scores say C2 is oversized but C1 tunnels in your jar, that gap is real: test the C1 pair, adjust on the fragrance side, or ask us on WhatsApp.

The step to production quantity

Once an arm passes, production wicks = candles × wicks per candle × (1 + a defect allowance). Worked example, labelled: 250 single-wick candles a month with a 2% allowance is 255 C1 wicks; buy 2 × 100 + 50 + 20 = 270 for ₹1,593.00 (15 left). A 500-pack (₹2,950.00) costs the same ₹5.90 a wick and ties up ₹1,357.00 more cash. If the confirmation shows C2 was right after all, 260 C2 wicks are ₹2,454.40. Reorder point = daily use × your lead time + safety stock; CSI publishes no lead times, so ask on WhatsApp. Keep using the sheet in production: one candle per batch, one session, six scores, is a cheap early warning when a wick or oil lot changes (what to retest when the wick supplier changes).

What to buy, and what to skip

Five items for the protocol and the confirmation, chosen on page statements, price and stock on 7 October 2026. CSI publishes no burn, soot or glass data, so none is ranked on performance, and each card says when not to buy.

Skip for now: any 500- or 1,000-pack before approval; a new oil or wax while the verdict is still open (one variable at a time); the 5.5 cm cutter and the trimmer if the ₹177.00 cutter reaches your wick; and our Pen Thermometer for glass, which it is not for.

Frequently asked questions