The wick goes out in the candle you poured: what it tells you

You poured a batch, lit a test candle and the first hour went fine. Then the flame got smaller, the melt pool stayed tight around the wick, its tip stayed red for a while and then it went out. Or you heard it from a customer, who wrote to you in the same words we’ve also found in our own reviews: "after a short while the candle simply stops burning, the wick glows a little and then goes out" (translated from Romanian).

When the pool stays tight and the flame shrinks until it goes out, the first hypothesis is that the wick is smaller than the candle needs: its flame no longer melts the wax out towards the edge, the pool deepens around it, and at some point the melted wax covers it. It’s a hypothesis, not a verdict. Before it, you check something simple: how much wick sticks out of the wax. After it, you look for what changed compared with the batch that burned well: the wax, the fragrance, the dye, the diameter, the wick or its batch. That’s where you start, not from a new wick picked by guesswork. And if the same candle burned well the first time and only went out at a later lighting, you also look at how it burned the first time.

Below, in order: what happens in the pool before it goes out; what you changed last and what each change does to the wick; the test that finds the cause without guessing; what you reply to the customer who writes that the candle went out. It’s written for anyone who pours, whether it’s their first batches, the candles they already sell or production at volume.

I’m Sînziana. In our workshop in Maramureș, Romania, we’ve been pouring candles since 2010, in moulds and in glasses, and we sell on the wicks and waxes we work with. What you find here comes from the manufacturers’ data sheets and from what we’ve written on our wick pages and in our wick articles, after test burns; where I don’t have a test of our own, I tell you so.

Why does the wick go out and leave a red dot?

Because the flame has nothing left to live on. The wick burns the wax it draws up from the pool around it; if it’s too small for that candle, the pool stays narrow and deep, the melted wax gathers around it faster than it can burn it and covers its tip. The flame drops, a red dot is all that’s left of it, then not even that.

What happens in the melt pool before it goes out

You can see it long before, if you know where to look. With the right wick, the pool widens towards the edge; in a container candle it reaches the walls. With a wick that’s too small, the pool stays a tight circle in the middle, the edges stay hard, and the flame sinks into an ever deeper hollow. On our wick pages we’ve described this kind of burn in the words you see in the glass: for containers, "a shallow pool that doesn’t reach the walls"; for moulds, the melt circle that "falls behind" and the wax that "doesn’t reach the edges".

You note one more thing: the moment. Did it go out in the first few minutes, after an hour, or only at the second or third lighting? Each answer leads somewhere else, and below I show you where.

And you look at the length before the size. The KeraSoy 4130 data sheet asks for the wick to be kept trimmed to ¼ inch, about 6 mm, and the pictogram on our boxes says one centimetre at most, as we wrote in the article on the first burn. A wick trimmed much shorter than that tells you nothing about the size: first you light it at its proper length, and only then do you judge it.

What do the wax data sheets say about a wick that’s too small?

They say the same thing, almost word for word, on three data sheets for container waxes in our range: KeraSoy Container 4130, EcoCoco and EcoOlive. A wick that’s too small tunnels and gives a smaller flame. Natural waxes tend to need bigger wicks than paraffin. Fragrance, colour and the shape of the candle weigh heavily in choosing the wick. If the flame is weak or unstable, the data sheet sends you to try another type of wick, and the test burn is done after the candle has stood for 48 hours from pouring.

None of them gives you a wick size. They give you the direction, and you find the size by testing, on your recipe. All three also carry the sentence that closes the discussion: every combination of wax, dye, fragrance and wick, with the container or the size of the candle, is burn-tested.

Why it matters that you poured it yourself

Because you have access to the wick, and the buyer doesn’t. Someone who bought a ready-poured candle has a few things within reach: a long first burn, clearing the wax from around the wick once it has hardened, relighting. We wrote them down in the article on a candle’s first burn, together with how you tell a tunnel left by putting the candle out too early from a wick that’s too small.

If the candle is yours, the list gets longer. You can change the wick, the wax, the fragrance and dye doses, the diameter. That’s why the useful question is no longer "what do I do with this candle?", but "what did I change in this batch?". One condition first: the test candle had a long first burn. If you put it out after half an hour and it dug a tunnel, you tested the first burn, not the wick.

What did you change last in the recipe?

If the same recipe burned well in earlier batches, you start from the last change: the wax, the fragrance, the dye, the diameter or the wick. Each of them moves the right wick, and the table below shows in which direction, according to the manufacturers’ data sheets and our wick pages.

You moved to a vegetable wax with the wick you had before

Here the wick falls behind without you having touched it. The data sheets of natural waxes say they tend to need bigger wicks than paraffin, and on our pages we’ve written what that means in practice. For the cotton wick for moulds: in 100% soy or coconut wax, the wick chosen for stearin may be undersized, so you test a size up. For the waxed wick for containers: soft vegetable waxes, like soy and coconut, tighten the melt circle compared with paraffin, so you consider a burn diameter one step up and confirm by testing. We also wrote about this in the article on types of wax: the wick doesn’t move with you automatically when you change wax family.

A size up means the next size in the same series: for the cotton wick for moulds, from 3x8 to 3x10; for the waxed wick for containers, from one burn diameter to the next. If the old wick is within your diameter’s range, you go up a single size and test. If it’s below the range, you start straight from the size in the table for your diameter, then test. What you don’t do is jump several sizes past the table, to be safe: the same data sheets say a wick that’s too big makes soot, speeds up the burn and makes the candle run down the side.

There’s another trap, a smaller one. On the page of special wick no. 5 we write that the manufacturer’s documentation covers beeswax, paraffin, stearin up to 15% and rapeseed, not soy or coconut. If you took it from your rolled candles and put it in a soy glass, you changed two things at once.

You added more fragrance or dye

The wick burns everything in the wax. On the page of the wick for moulds we write that the oils and the dye make burning harder and that, at a high load, the test on the final recipe remains mandatory. The wax data sheets put fragrance and colour next to the shape of the candle, among the things that weigh heavily in choosing the wick.

If you changed the fragrance, not just the dose, read one more line. The KeraSoy 4130 data sheet says some fragrances react badly with the wax and can give, among other things, a weak flame, and the effect is greater with fragrances made for paraffin candles. So the question is also what wax the fragrance was made for, not just how much you put in.

You take the maximum dose from the wax’s data sheet: for KeraSoy 4130 it says up to 10–12%, for EcoCoco and EcoOlive between 5 and 12%. Below that ceiling, fragrance still changes the wick. The ceiling tells you how much fragrance the wax takes, not how much your wick can carry. We wrote about dose and burning separately, in the guide to fragrance in candles.

Here the first test isn’t a bigger wick. You pour two pieces with the same wick, one with the fragrance and dose from before, one with the new ones. If the first burns and the second goes out, you’ve found the change, and only then do you choose: you lower the dose, change the fragrance or, if you want to keep it, test a size up. And if the flame is weak or unstable, the data sheet sends you to another type of wick, not just another size. A bigger wick that burns well gives you a possible solution; on its own, it doesn’t tell you why the old one went out.

What you don’t do: you don’t raise the fragrance even more to "make up for" a candle that smells weak because it burns badly, and you don’t change the fragrance and the wick in the same test.

You poured wider or changed the type of wick

The diameter is the first figure the wick is chosen by, so a wider candle with the old wick can fall outside its range. You check in the table whether the new diameter is still in the same range. For the cotton wick for moulds, our starting points, tested on recipes with stearin, are 3x6 for 2–3 cm, 3x8 for 3–5 cm, 3x10 for 5–7 cm and 3x12 for 7–9 cm. For the waxed wick for containers, you choose a burn diameter roughly equal to the inside diameter of the glass, then the height by the depth. For special wick no. 5, on its page we write that it tunnels above 4 cm in poured candles and above 4.5 cm in rolled ones; there we move to no. 7. If you don’t want to search through tables, enter the new diameter and the wax in the wick calculator and see the wick’s range straight away.

When you change the type of wick, the old figures no longer apply. Special wick no. 5 comes unwaxed. On its page we write that it’s first soaked in a thin layer of melted wax and that without this priming the first lighting is temperamental; it also says there that it’s fitted with the V of the braid pointing down, towards the base, because the other way round the flame isn’t stable. If your candle goes out in the first few minutes, with an unwaxed wick, you start here.

Wood is another story. It’s sized by width, not by the number of threads, and cotton tables don’t carry over. The 10 mm straight wooden wick holds on its own, in our tests, up to about 5–5.5 cm, depending on the wax; beyond that, the flame falls behind and the edges stay cold, and there you use two wicks or move to a greater width. The details are in the article on wooden wicks.

How to find the cause without guessing

You set side by side two versions that differ in a single thing, according to the hypothesis you’re checking: the recipe that worked next to the new one, or the current wick next to one a size up, each in its own piece, in the final form. A short test rules out the obviously wrong versions; the confirmation comes from the whole candle, burned in sessions, on your recipe.

Why you change one variable at a time

Because otherwise you don’t know what fixed the candle. If you move to a bigger wick and, in the same batch, also lower the fragrance, and the candle burns well, you haven’t learned anything you can use for the next batch. On our wick pages, cotton and wood, it says the same thing: with a new batch, a test piece, and you change one variable at a time.

For each test candle you note: the wax and its batch; the fragrance and its dose; the dye and its dose; the additives, if you used any; the wick, with its series, size and batch; the shape and diameter of the container or the piece; how many hours have passed since pouring; how much wick stuck out of the wax before each lighting; how long each burn lasted and where it burned; and when it went out, if it did: after how many minutes, at which lighting. During the test burn, the wax data sheets ask you to also look at the tip of the wick, to see whether it’s "mushrooming", meaning deposits of carbon and other substances that get in the way of its burning.

In moulds: the quick test, then separate pieces

On the page of the wick for moulds we wrote down the quick test we do in the workshop: the same final recipe, 3–4 different wick sizes in the same small container, 2–3 cm thick, the wax left to harden completely, all lit at once and read after 20–30 minutes. A melt circle that’s too small shows a wick that’s too weak, an unstable flame one that’s too strong. It’s an elimination test: it takes the obviously unsuitable sizes out of play.

It isn’t the choice as well. In the same container, the wicks melt the same wax, so you don’t see how each one burns on its own, in a candle with a single wick. For the sizes that remain, you pour one identical piece each, in the final form, and burn them spaced apart, on a surface that doesn’t burn, in front of you. A flame that rises and smokes you put out on the spot and note as too strong.

The confirmation comes from the whole candle. You burn it in sessions, the way whoever buys it will burn it, down towards the end, and you watch above all whether it gets past the point where the old one went out.

In a glass: 48 hours of rest, then two hours of burning

With containers, the wick is read in the glass, not in the flame. You let the candle stand after pouring: the data sheets ask for 48 hours, and on the waxed wick pages we write 48–72. Then you burn it for two hours without a break, in front of you, and look at the pool from the side. Our benchmark for a glass, written on the waxed wick pages and in the guide for containers, is a pool that reaches the walls evenly without going deeper than half a centimetre. It’s the benchmark we calibrate our own container candles by, not a figure from the manufacturer’s data sheet, and you read it on your glass and your recipe. A small flame and a pool that doesn’t reach the walls mean a wick that’s too small, so at the next test you go up one burn diameter. If the pool goes deeper than half a centimetre or the glass gets hot, you put the test out on the spot, and at the next one you go down a size.

The two hours are the minimum, not the confirmation. In the guide for containers we wrote that overheating sometimes only shows up in the third or fourth hour, so a test that looks good at the second hour is worth watching further. You confirm the size on the whole glass, burned in sessions down towards the bottom.

The full protocol, with the diagnostic table for the other side, the wick that’s too big, is in the guide to wicks for containers.

What you reply to the customer who writes that it went out

Questions, before explanations. The answers don’t split the blame between you and the customer; they narrow down the hypotheses, and some can only be checked with a photo.

What you ask them and what photos you ask for

1. How long did it burn the first time, and what did the pool look like when they put it out? A short first burn, after which the candle burns in a hollow, points to first-burn tunnelling. You can send them the article on the first burn, with the things they can do themselves. But a short first burn doesn’t, on its own, rule out a wick that’s too small.
2. Did it go out from the first lighting or only later? If it drowned from the first burn, with the ring of wax intact after a long burn, the hypothesis of a wick that’s too small becomes the most likely, and it’s yours to check.
3. How much wick sticks out of the wax now? You ask for one photo from above, with the wick and the pool, and one from the side. From them you see whether the wick was trimmed too short, before you suspect the size.
4. Where and for how long did it burn, each time? How many lightings, how long each one lasted, in what room.
5. Which candle is it? From which batch, what diameter, what fragrance. You put the answer next to your pouring notes: if that batch is the first with the new wax, the new fragrance or a new batch of wick, you’ve found the last change.

We answer this message with questions, not an apology; we wrote that in the article on the first burn too. It isn’t politeness. Without these answers, any explanation is a guess, and the customer leaves either with a blame that isn’t theirs or with a promise the next batch won’t keep.

What you send us if the wick is from us

If you’ve done the test and still can’t tell, send us the details and two photos, and we’ll look at it together. The details are the ones from your notes: the wax and its batch, the wick with its series, size and batch, the fragrance and the dye with their doses, the additives, the shape and diameter, how much wick stuck out of the wax, how long it burned each time and when it went out. The photos: one from above, with the pool, and one from the side. Write to us on WhatsApp or call us on +40 726 162 810 (we answer in English).

When a candle that burned well starts going out, the first question isn’t which new wick to buy. It’s what changed since the batch that burned well: in the recipe, in the wick or in the way it burned.