What does a candle wick do?
A wick carries liquid wax toward the flame through capillary action. The wick’s construction controls how it bends, how much fuel reaches the flame, and how stable the flame remains. A type is not a guaranteed size recommendation.
The CandleScience wick-sizing guide also treats wick choice as a system decision: size, wax, vessel, and burn observations need to be considered together.
How do cotton and wood constructions compare?
- Flat-braided cotton: A common starting point for container candles. The braid can curl as it burns, helping manage carbon buildup, but the final result still depends on size and formula.
- Square-braided cotton: Often selected when a stiffer braid or a different melt-pool behavior is useful. It is still tested as part of the complete candle.
- Cored cotton: A cotton braid around a supporting core. The core can add stiffness, which may help in some vessel or wax systems. Compare the construction with cotton wicks for candles when reviewing available formats. For a metal-cored wick, the U.S. Consumer Product Safety Commission’s candle FAQ states that lead in the metal core must not exceed 0.06% by weight.
- Wood: A rigid strip or layered wood construction. Wood can change flame character and sound, but width, thickness, wax, and fragrance load all affect performance. Wood wicks for candle making are one product-specific example of this family.
| Construction | What it changes first | What still needs testing |
|---|---|---|
| Flat or square cotton | Braid shape and stiffness | Size, wax, fragrance, and vessel heat |
| Cored cotton | Support and rigidity | Melt-pool width and flame stability |
| Wood | Flame character and strip dimensions | Width, thickness, wax, and fragrance load |
The Terre de Bougies guide also treats wick material, wax type, and vessel diameter as connected decisions.
Which variables change the starting wick size?
Start with the inside diameter of the vessel, then record the wax blend, fragrance and dye load, wick construction, and cure time. A wider vessel generally needs a wick system that can support a wider melt pool, but a larger wick is not automatically better. Fragrance, colorants, additives, and wax hardness can all change the burn.
Use supplier charts as a starting range, not a final answer. Reserve the category phrase candle wicks for browsing; this guide explains the reasoning behind a test plan.
How should you run a burn test?
- Choose two or three nearby wick sizes or constructions.
- Keep the vessel, wax, fragrance, dye, fill weight, and cure time controlled.
- Trim each wick to ¼ inch (6 mm) before lighting, following NFPA candle-safety guidance.
- Record flame height, flicker, soot, mushrooming, melt-pool width, vessel heat, and total burn behavior.
- Repeat the test across several burn cycles before selecting a formula.
Example test log: Imagine a hypothetical vessel. Record its inside diameter, wax blend, wick series and size, fragrance load, dye, cure time, and wick length before each burn. Compare nearby wick options while keeping the other variables steady; log flame, soot, mushrooming, melt-pool width, and vessel heat at consistent intervals. This is a plan for observations, not a claimed test result.
An under-wicked candle may tunnel or leave unmelted wax at the edge. An over-wicked candle may produce an oversized flame, excess soot, or too much vessel heat. These symptoms point to a test adjustment; they do not prove that one wick family is always wrong.
Burn testing evaluates a candle’s performance; it does not replace safe-use precautions. NFPA’s educational reference says:
“Before burning, always trim the wick to ¼ inch (6 mm).” — NFPA, Educational Messages Desk Reference
Follow that guidance and the candle maker’s safety instructions during every test. For example, a test log can compare two nearby wick options while all other variables remain unchanged; it should record observations rather than imply a guaranteed result.
Frequently asked questions
What is the best wick for soy wax?
There is no universal best wick. Soy wax, vessel diameter, fragrance load, dye, and cure time all affect the result, so compare nearby options in a controlled burn test.
Are wood wicks better than cotton wicks?
Wood and cotton create different flame and sensory experiences. Choose by the desired candle behavior and the evidence from testing, not by material alone.
Why does a candle tunnel?
A wick that is too small, a short first burn, wax hardness, or vessel geometry can contribute. Check the complete system before changing only the wick.
How do I know a wick is the right size?
Look for a stable flame, an even melt pool that reaches the vessel edge in a reasonable time, limited soot, and acceptable vessel temperature over repeated cycles.
