Most of us look at the wax and the scent when we pick a candle. The wick gets barely a glance. Yet candle wick candles live or die by that small piece of string. It decides how big the flame is, how wide the wax melts and how evenly the scent comes out. So what is a wick made of, and is there anything in it you should worry about?
How the wick in candle wick candles really works
A wick does not burn the wax as a solid. It works like a straw. The flame melts the wax around it, and the wick draws that liquid wax up its threads. Scientists call this capillary action, the same pull that lets a paper towel soak up a spill.
At the top, the heat turns the liquid wax into a gas. That gas is what actually burns. So the flame you see is burning wax vapour, with the wick acting as the pipe that feeds it.
Why does wick size matter?
A thicker wick pulls up more wax. That gives a bigger flame, a wider melt pool (the circle of liquid wax around the wick) and a faster burn. Too thin, and the candle can tunnel down the middle.
What goes into candle wicks
Most wicks use braided cotton. Many have a stiffener inside to keep them standing upright in the hot wax. Common choices include:
- Plain braided cotton
- Cotton with paper woven in
- Cotton wrapped around a thin zinc core
Flat braided wicks bend over as they burn. The tip curls into the flame and burns away, so the wick partly trims itself. Even so, a quick snip with a candle wick trimmer before each light helps keep the flame neat.
The metal wick myth
You may see posts online warning that any wick with metal in it contains lead. That mixes up two different things. In 2003 the US safety regulator, the Consumer Product Safety Commission, banned lead cored wicks. It listed zinc, cotton, paper and synthetic fibres as the safe options most makers already used. A zinc core is not a lead core. If you are unsure what is in a wick, ask the maker. A good one will tell you.
Quick answers
What is a candle wick made of?
Most candle wicks use braided cotton. Some have paper or a thin zinc core inside to keep them upright. The US banned lead cored wicks in 2003.
Do candle wicks trim themselves?
Flat braided wicks partly do. They curl into the flame as they burn and the tip burns away. A quick trim before lighting still keeps the flame steady and tidy.
A good wick is one you never have to think about. Each tealight in our Advent Calendar sits on a four-footed base for a steady, even flame. From 1 December, you can watch 24 of them at work, one evening at a time.
Related reading
- Candle Wick Trimmer Tips: Why 5mm Is the Length to Aim For: the trimming habit that keeps a flame neat
- Soy vs Paraffin Candles: What the Research Actually Says: the other half of the story, the wax
- Candle Safety at Home: Simple Habits for Winter Evenings: simple habits for safe winter burning
