The wick is the one part of a candle most people have never thought much about. It's thin, it's there to burn, and it does its job invisibly when everything else is right. But wick type is one of the three primary variables that determine how a candle actually performs, and switching from cotton to wood changes the burn in ways that are both visible and audible. See The Anatomy of a Good Candle for how these variables work together.
What a Wood Wick Is
A wood wick is a thin flat strip of natural wood that functions as the wick. Unlike cotton wicks, which are braided and cylindrical, wood wicks are flat and rigid. They're treated to burn at the right rate for candle use without being extinguished by the wax pool.
The flat profile of the wood wick produces a wider, lower flame than a cotton wick would in the same vessel. That flame shape produces a wider melt pool at lower heat, which is exactly what you want in a larger jar, where you need the pool to reach the edges without the flame running excessively hot. Getting the wick size right for our specific soy wax formulation, fragrance load, and jar diameter requires testing every configuration. There's no standard size that works across variables. See What Makes a Candle Burn Well.
The Crackle
The most immediately noticeable difference is the sound. Wood wicks produce a low, intermittent crackling sound as they burn, similar in quality to a small fireplace, though much quieter. This happens because the wood contains trace moisture and organic material that produces micro-pops as it combusts.
This isn't a defect or an indication of an uneven burn. It's simply what burning wood sounds like. We chose wood wicks in part for that crackle. The sound of a small fire belongs with scents built around wood, evening, and warmth indoors.
How to Care for a Wood Wick
Wood wicks need attention between burns, much like cotton wicks do. They develop a char at the tip from the previous burn that can obstruct the next one if left in place. Before lighting, remove the charred portion. It breaks off cleanly, leaving a fresh wick face ready to light. A wick trimmer makes this easy. A wick left choked with char will produce an oversized, uneven flame; a cleared wick produces the low, wide burn that defines the performance we're after.
If your candle doesn't light easily, the wick almost certainly needs clearing. This is the most common wood wick issue and the easiest to solve.
For more on keeping a candle burning well, see How to Make Your Candle Last Longer. Every candle in the candle collection burns on a wood wick.