My Wick Supplier Is Out of Stock and Another Supplier Says Their Wick Is an Equivalent Size — Can I Use It Without Retesting?

What “equivalent size” actually means

When a supplier says their wick is an equivalent size, they are usually matching one number or one description to another — a size code, a nominal width, a recommended jar diameter from their own chart. That comparison can be honest and still not tell you how the wick will burn in your wax, with your fragrance, in your jar. There is no shared industry scale that makes one maker's size mean the same thing as another maker's. Each series is built on its own braid, its own cotton or cotton-blend yarn, its own priming wax and its own tab. Two wicks can sit on the same line of two different charts and still deliver different heat to the same candle.

So the honest reading of "equivalent" is: a reasonable starting candidate. That is useful. It narrows the search. What it does not do is carry over your old burn-test results. Those results were a measurement of one specific system — wax, oil, load, jar, wick — and you have now replaced one of its five parts. The rest of this page shows exactly which of your earlier results survive the change, which ones must be repeated, and how few candles it takes to find out. The same logic applies whether the replacement comes from another supplier or from CSI: we sell Eco Candle Wicks, Cotton Braided Wicks Ready Made, Performance Wooden Wicks and a Braided Wick Roll, and we do not publish their construction details or call any of them equivalent to another brand's size.

Read the last row twice. The only numbers that decide whether the wick is safe and saleable are the ones produced in your own jar, with your own wax and oil. That is not a criticism of the other supplier. It is simply how candles work, and it is why the question "can I use it without retesting?" has a short answer.

The five-step wick-change method

The nineteen posts that follow this one each take a single wick scenario — a size up, a size down, a new tab, cotton to wood, one wick to two — and add what that scenario needs. The backbone is the same in all of them. It is a small change-control routine that a one-person candle business can run on a kitchen table, and that a team of ten can write into its procedures.

The retest matrix for a like-for-like wick swap

Here is the matrix for the exact situation in the title: same wax, same fragrance at the same load, same jar, and only the wick supplier changed. Each line says which bucket the earlier result falls into and why. Where a sibling post goes deeper on one line, it is linked.

Count the lines. Two are KEEP, two are CONFIRM, seven are REPEAT, and one is NEW only if you are changing wick type. That is the honest shape of a wick change: most of the combustion work has to be done again, but none of the fragrance-and-wax development does. You do not need to re-establish your load, re-cure for cold throw or redo colour. You need to burn candles carefully and write down what they do. The storage-testing post covers why long-term storage tests are mostly KEEP after a wick-only change, and the full retest checklist lists every combustion line with its recording method.

The minimum test: a bracket of two candidates against a control

Because nobody can promise that a named size from a new supplier sits exactly where your old wick sat, the efficient test is a bracket: one candidate you expect to run slightly cooler and one you expect to run slightly hotter, both against the control. If both fail in opposite directions, you know the right answer lies between them and you ask the supplier for the size in between. If one passes, you have your wick. If both pass, pick on cost and the secondary lines. This page prices the bracket with two CSI wicks — Eco Candle Wicks Thin C1 and Thick C2 — because they are the pair CSI lists. CSI does not publish their construction, and we are not saying either one matches your old wick. They are candidates, nothing more.

Pour all nine candles from one melt so the only difference between the groups is the wick. Cure them together. The cure checkpoint you already use for this recipe still applies — the wax and oil have not changed — so if your approved recipe burns at 7 days, test at 7 days. Then run the screen: 3 burns of about 3–4 hours each with a full cool-down between them (a commonly used cycle — treat it as a working practice). Record every line on the scoring sheet for every candle. If a candidate fails a safety line during the screen, stop that candidate. The survivors keep burning to the end of usable wax, because end-of-life behaviour is a REPEAT line and cannot be skipped.

The scoring sheet: every line judged against the control

Copy this sheet once per burn. The control column is filled in from the control candles in the same session — not from your memory of how the old wick used to burn, and not from a sheet written months ago in a different season. The acceptance column is written before you light anything, so the result cannot bend the rule.

The 0–3 scales are deliberately coarse: 0 none, 1 slight, 2 clear, 3 heavy. Coarse scales are easier to apply consistently than fine ones, and consistency is what makes a side-by-side comparison worth anything. CSI publishes no numeric limit for flame height or jar temperature, and neither does this page. The safety test is relative and absolute at once: no worse than your approved control on every safety line, and within your jar supplier's guidance and the recognised candle fire-safety standard you work to. ASTM F2417 is a commonly cited US candle fire-safety standard; if you work to it, use its methods — we quote no numbers from it here.

The decision rule: pass, fail or escalate

Two points about this rule. First, a hotter wick that throws better is a fail, not a trade-off. The whole point of a like-for-like wick replacement is to get back to the approved candle, not to redesign it by accident. If you want a stronger candle, that is a formulation project with its own tests, not a stock-out fix. Second, "escalate" is not a polite pass. If three candles of the same candidate disagree, the variation is a finding in itself: either the pour, the centring or the wick is inconsistent, and you would not want that in production.

The priced CSI test kit

The kit below makes the nine-candle bracket test at 200 g and 8% fragrance, with a 5% pour-loss allowance (a labelled working assumption). The oil is Lavender Fragrance Oil, the wax Luxury Soy Wax Chunks — rated by the wax maker up to 13% fragrance load, so 8% sits comfortably inside it. Each candle takes 16 g of oil and 184 g of wax. Use your own production wax and oil if they differ: the point of the test is to change only the wick.

The wax and oil in each test candle cost ₹234.78 on average at these pack sizes, before wick and jar. The oil is dearer per gram here than in production because 15 g, 50 g and 100 g bottles carry most of the per-gram premium in the catalogue — Lavender is ₹7.00 a gram at 15 g and ₹5.40 at 50 g and 100 g. That premium is the price of testing small, and it is worth paying. Labour, electricity and your time are not included; if you want to cost them, use your own figures (for example, an hour of your time at a rate you set) rather than ours.

Put the kit against what it protects. A 500-candle run of this same 200 g lavender candle, at CSI's listed prices for 1 kg of Lavender (₹5,221.00), Luxury Soy Wax Chunks at ₹599.00 a kilo, Eco Thin C1 wicks at ₹5.90 and White Matte jars at ₹70.80, is ₹1,35,226.00 of materials. The test kit is 2.4% of that. If the new wick turns out to run hot in the lower third of the jar, you find out on nine candles, not on five hundred.

Releasing the new wick into production

A pass on the test bench is not yet a release. Three more steps turn it into something you can repeat in six months without re-arguing it.

Which sibling answers your exact wick change

This page is the hub for every wick-change question in the series. Each sibling takes one scenario and adds only what that scenario needs; none of them repeats the method above. Find your situation in the left column.

Wick changes rarely happen alone. If your wax or fragrance changed at the same time, the tests become harder to read, because a result could come from either change. The two-changes post explains how to separate them, and the one-variable post explains why it is worth waiting for one change at a time whenever you can.

Where wick swaps go wrong

Testing without a control. A new wick burned on its own tells you what it does, not whether that is different from before. Rooms change with the season; a flame that looks fine in September can look different in May. The control, burned in the same session, removes that noise.

Testing in a different jar. If your production jar is out of reach and you test in a spare jar of a different width, you have changed two things. Melt-pool results scale with diameter: a 7.6 cm pool and a 7.9 cm pool differ by about 8% in surface area. Test in the production jar or not at all.

Stopping at the first burn. Covered above, and worth repeating: early burns flatter a wick. The lower third of the jar is where heat and drowning show up, and where most returns come from.

Changing the wick and the trim together. If the new wick arrives longer or shorter, trim both control and test candles to the same length before every burn. Otherwise you are testing your scissors.

Treating the supplier's chart as a result. A chart is the supplier's measurement in their conditions. It is a good reason to choose a first candidate and a poor reason to skip a test. We say the same about our own wicks: CSI does not publish a wick-size-per-diameter chart, and we would rather you burned a candle than trusted one.

Frequently asked questions