Reading the Candle
What the top of a cooled candle is trying to tell you.
Your first candle will have a defect. Mine did. The trick is not to avoid defects, it is to read them cleanly so you know which single variable to change next time.
Three failures cover most of what beginners see. Tunnelling, wet spots, and a sunken top with a hole around the wick. Each one points at a different step of the pour.
Why do my candles keep going out (tunnelling explained)
A narrow melt pool that burrows straight down and leaves a wall of unmelted wax on the sides. It looks like an under-wicked candle, and that is often true, but not always. Before you go up a wick size, check the first burn: did you let the melt pool reach the edge before extinguishing? A candle remembers its first burn. If you blew it out early, it will tunnel forever.
If the first burn was long enough and you still see a tunnel by burn three, go up one wick size and keep everything else the same. Change one thing at a time or you are guessing.
Why do wet spots appear on candles (and how to fix them)
Cloudy patches where the wax has separated from the glass. Almost always a temperature problem, almost never a wax problem. The vessel was too cold when you poured. Warm the glass to at least 35°C next time. The hairdryer trick above solves this cleanly.
Why do candles sink in the middle (the sinkhole fix)
As wax cools it contracts by several percent. Around the wick, where the last bit of hot wax stays fluid longest, you get a small crater. This is a poured-too-hot problem or a poured-too-fast problem, sometimes both.
The fix is a second pour. Reserve about 20 g of your original melt, keep it warm, and top up the crater once the main pour has set for an hour. Or heat the surface with a heat gun for ten seconds until the top melts and self-levels. Both work.
Wick centring
Half of what looks like a wick problem is a wick-position problem. The wick moves during the pour. Use a centring bar or two wooden pegs across the top of the vessel to hold it plumb until the wax sets. The diagram on the next page shows three methods, ranked by how forgiving they are.
| Symptom | Likely cause | Fix | Prevent |
|---|---|---|---|
| Narrow melt pool, wall of unmelted wax after burn 3 | Under-wicked, or first burn was cut short | Full-melt-pool first burn, then step up one wick size only if it repeats | One-hour-per-inch first burn, single-variable change per test |
| Cloudy patches between wax and glass | Vessel too cold at pour | Warm vessel to 35°C with a hairdryer before pouring | Pre-warm every vessel; log ambient temperature per batch |
| Sunken crater around the wick | Poured too hot or too fast; contraction concentrated at the wick | Second pour or heat-gun re-melt of the top surface | Pour inside the wax-family window; reserve 20 g for top-up |