"Why are my candles cracking?" comes up more than any other question from people making candles at home. Cracks usually appear on the surface as the wax sets, and they almost always come down to how the candle was poured or cooled. Below are six causes, how to fix each one, and how to rescue a candle that has already cracked.
1. The candle cooled too quickly
When the outside of a candle cools and hardens faster than the centre, the surface shrinks and splits. This is the usual culprit in the UAE, where air conditioning keeps rooms cold and moves air across the candles.
To fix it, let candles set somewhere warmer, away from AC vents, fans and open windows. A steady room temperature matters more than a warm one.
2. The candles went in the fridge or freezer
Chilling candles to speed them up makes the wax set unevenly and turn brittle, and they crack or pull away from the glass.
To fix it, always let candles set at room temperature. Container candles usually need several hours, and it is best to leave them overnight.
3. The pouring temperature was too hot or too cold
Wax poured too hot shrinks more as it cools, and wax poured too cold sets before it settles, both of which can crack the surface. Every wax has its own recommended pouring temperature, so check the one for yours and measure it with a digital thermometer rather than guessing.
To fix it, pour at the temperature your wax recommends. If you still get cracks, try pouring about 5°C warmer or cooler and see which works in your room.
4. Air bubbles from stirring too hard
Stirring fast or whisking the wax traps tiny air bubbles, which rise and burst as the candle cools and leave pits and cracks on the surface.
To fix it, stir slowly and gently for about two minutes when you add the fragrance oil. Tap the side of the container after pouring to bring bubbles to the top.
5. The candles cooled unevenly
Jars placed close together trap heat between them, so the sides that face each other cool more slowly than the rest. The difference is enough to crack the surface.
To fix it, space jars about 5 to 8 cm apart, and set them on a wire rack so air can reach the bottom as well.
6. The wax was poured too fast
Pouring quickly traps air and makes the wax cool unevenly.
To fix it, pour slowly and steadily from a wax melting pot with a spout, aiming at the centre of the jar.
Why do soy wax and beeswax candles crack differently?
Beeswax is hard and shrinks a lot as it cools, so beeswax candles crack and pull away from the sides of the jar more easily than soy candles. Pouring beeswax a little warmer and cooling it slowly helps. Soy wax is softer and cracks less, but it is prone to rough, bumpy tops and white "frosting" on the surface, which are cosmetic and don't affect how the candle burns.
How to fix a candle that has already cracked
- Use a heat gun: gently melt the top few millimetres of wax with a heat gun. The melted wax flows into the cracks and sets smooth.
- Top it up: when you pour a batch, keep a little wax aside. Melt it and pour a thin second layer over any cracks or sinkholes once the candle has set.
- Oil the mold: for beeswax in molds, a thin layer of coconut oil inside the mold helps the candle release cleanly without cracking.
Find wax, wicks, jars and tools in our candle making collection. If you are just starting out, read where to buy candle making supplies in Dubai.