How wood wicks work, and why yours won't stay lit
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A wood wick is a thin, flat strip of wood held upright in a metal clip. Melted wax soaks into the grain and burns along its top edge, giving a wide, low flame and a soft crackle. Wood wicks go out for three common reasons: the wick is too thin for the wax, the fragrance load is too high for the wick to draw through, or it was trimmed too long or not cleaned of char. Unlike cotton, a wood wick is sized by two measurements, thickness and width, and each one controls a different part of the burn. Below: sizing from two sellers' published guidance, trimming, and diagnosing a wick that fails.
How a wood wick burns
A cotton wick draws wax up a braid. A wood wick draws it along the grain of a flat strip, and the flame sits along the wick's top edge rather than at a point. That is why a wood wick's flame is broad and low; one seller describes its booster wick as designed to resemble a fireplace with "a horizontal flame shape" [1]. The crackle comes from the wood itself, and Supplies for Candles describes it as "a gentle crackling sound" [2].
Because the flame is spread along an edge, a wood wick is less forgiving than cotton. It needs enough wax reaching the whole edge to stay lit, and enough wood to keep burning as the wax gets deeper.
Sizing: thickness and width do different jobs
Makesy, a candle supply seller, puts the two dimensions this way in its wood wick selection guidance: thickness is "the bulk of wood material" and mainly controls the burn and the flame size, while width mainly controls the melt pool diameter [3]. Its wicks come in thicknesses of .01, .02, .03 and .04 inch and in widths starting at .375 inch and going up in steps (.375, .5, .625 and so on) [3].
Two supplier charts and notes, side by side. Each is that seller's guidance for the wicks it sells. No sizing guide published by a wood wick manufacturer itself could be found, so every figure below is a seller's, labeled as such, and your burn test decides.
| Seller | What it publishes | Figures |
|---|---|---|
| Supplies for Candles (UK) [2] | A size chart by container diameter, called "a rough guide" | S: 50 to 63 mm, 9 mm wide; M: 63 to 76 mm, 12 mm wide; L: 76 to 88 mm, 16 mm wide; XL: 88 to 101 mm, 19 mm wide. All 1 mm thick |
| Makesy [3] | Thickness and width steps, wax pairing and test targets | 100 percent soy "almost always" needs .04 thickness; its coco apricot creme wax starts best at .02. Test targets: full melt pool in 2 to 3 hours, pool about 1/2 inch deep, flame about 1/2 inch tall |
| Village Craft & Candle [1] | Product dimensions on a listing | A medium crackling wick is .5 inch (13 mm) wide and .04 inch (1 mm) thick, sold for soy and natural blends in containers |
Notice that .04 inch is about 1 mm, the single thickness Supplies for Candles sells and the thickness Makesy recommends for soy. Makesy's own pairings put the thinner wick with its coconut blend, starting it at .02 [3]. Supplies for Candles adds that a small amount of beeswax in a blend can increase viscosity and improve burn performance [2]. Makesy also notes that soy needs a thicker or wider wood wick than paraffin [4].
To choose a first test set: measure the inside diameter of the vessel, pick the width the chart gives for that diameter, choose a thickness for your wax, and then test that wick with one step thinner and one step thicker. Dyes, micas and fragrance load all change the burn, so test with the exact formula you plan to make [3].
Boosters
A booster is a narrow second strip of wood placed against the main wick in the same clip to add flame for wider vessels or harder-to-burn wax. One seller describes its largest booster as meant to work with its widest flat wicks, in the same clip, and mentions 100 percent soy in large candles as a use [5]. Treat a booster as a change of wick and test it the same way.
Trimming and lighting
Wood wicks are trimmed short, and the sellers' figures differ a little:
- Supplies for Candles: trim so that 5 mm or less of wick sits above the wax before lighting [2].
- Makesy: about 3/16 inch (about 5 mm) above the wax [3].
Both put the wick at around 5 mm. Remove charred wood after each burn, as one seller's instructions say [5], so fresh wood meets the wax. The same seller notes that a full melt pool may take several hours on the first burn [5].
When a wood wick fails: what you see, what it means, what to do
| What you see | What it likely means | What to do |
|---|---|---|
| Flame is small, sputters or goes out; wick will not stay lit | The wick is too small for the wax. Makesy ties a drowning or dead flame to an undersized wick [3]. Supplies for Candles says a wick that goes out usually means the wax blend does not suit it, often because the fragrance load is too high [2] | Move up one thickness at the same width (Makesy's example: .02 to .03) [3]. If the load is near your wax's maximum, test a lower load. Check the trim and clean off char |
| Goes out after the first few minutes, especially on relighting | Possibly charred wood left from the last burn, or a wick left untrimmed | Trim to about 5 mm and remove the char before lighting [2][3] |
| Good, steady flame but the pool does not reach the edge, or it tunnels | Width too narrow for the vessel | Keep the thickness and move up one width (Makesy: .02 x .5 to .02 x .625) [3] |
| Full pool in under 2 hours, large dancing flame, smoke or blackened wax | Wick too large; the candle is running hot | Drop to the next thinner wick (.02 to .01); if already at the thinnest, drop one width [3]. Supplies for Candles suggests carefully trimming a thin strip from one edge of an over-wicked wood wick [2] |
| Wick burns well at first, then drowns lower in the jar | Possibly a pool deeper than the wick can feed (Makesy's target depth is about 1/2 inch [3]), or debris in the pool | Test one thickness up for the lower half; keep the pool free of match ends and char |
| Pool weak with a single wick in a wide vessel | Vessel too wide for any single wick you have | Supplies for Candles suggests doubling up wicks or using a larger size [2]; a booster is another option [5] |
| Little or no crackle | Crackle varies from wick to wick, and no source read ties it to burn quality | Judge the wick by melt pool, flame and soot |
A wood wick that goes out is a different problem from a cotton wick that drowns, though they share causes; the cotton case and other causes of a candle that goes out are on a candle that keeps going out.
Testing a wood wick candle
Wood wicks are tested like any wick: chart candidate plus one step either side, same formula, side by side, hourly records, burned to the end. Makesy tests in 4-hour intervals against its three targets [3]. Its targets are one seller's, for its wicks; your own results decide. The general method is on how to size a wick, and moving up or down a size after a failed burn is on when to change the wick size.
Tell customers that a wood wick needs trimming to about 5 mm and cleaning of char before every burn. Customer instructions are covered on burn instructions to give customers.
If your wood wick still won't stay lit
Most persistent failures come back to fragrance load and wax fit. Check your load against your wax's limit on how much fragrance oil to use, then test one thickness up. If the candle goes out for other reasons (debris, dye, a deep pool), the causes are worked through on a candle that keeps going out.
References
- Village Craft & Candle, Crackling Booster .04-.5 Wood Wick (Medium) (product page), read October 22, 2026. https://villagecraftandcandle.com/products/wood-wick-medium
- Supplies for Candles, Wooden Wick (category page with size chart and notes), undated, read October 22, 2026. https://www.suppliesforcandles.co.uk/product-category/candle-wicks/wooden-wick/
- Makesy, A Guide To Selecting Your Wooden Wick, August 28, 2022. https://makesy.com/blogs/news/a-guide-to-selecting-your-wooden-wick
- Makesy, What Size Wooden Wick Should I Use?, August 4, 2020. https://makesy.com/blogs/news/what-size-wood-wick-should-i-use
- Bulk Apothecary, Wooden Wick Booster 3/4" x 5" (product page), read October 22, 2026. https://www.bulkapothecary.com/wooden-wick-booster-3-4-x-5-bag-of-25/
