Why Does My Candle Smell Weak When It Burns?
Short answer
A weak hot throw usually comes from a short cure, a wick that is too small or too big, a fragrance load that is too low or past what the wax holds, the wrong oil for the wax, or a mixing or temperature slip. Change one thing at a time and burn test each change.
Hot throw is the smell of a candle while it burns. When it is weak, the cause is usually one of a handful of things: not enough cure, the wrong wick, the wrong fragrance load, an oil that does not suit the wax, or a mistake in how you added it. Wick, wax, fragrance and vessel work as one system, so change one thing at a time and write down what happens.
What are the usual causes?
It has not cured. The Flaming Candle says skipping cure time is one of the easiest ways to lose scent, and that most soy and blended waxes need at least a week, and its FAQ gives 7 to 14 days. Paraffin needs less, but test it. NorthWood lists a 1 to 2 week cure for soy and coconut and 48 to 72 hours for paraffin. See our cure guide.
The wick is too small. Midwest lists the signs as a small melt pool, a low flame or a drowning wick, and says to try a wick 1 or 2 sizes up. If the pool never reaches the edge, little wax is warm enough to release scent. CandleScience wants a pool reaching the edge and about 1/4 to 3/4 inch (6 to 19 mm) deep.
The wick is too big. Midwest says a big flame, soot and a deep melt pool can burn the scent off too quickly, and suggests going down 1 or 2 sizes. The Flaming Candle says an oversized wick can burn hot enough to destroy the fragrance. A too-big wick is also a heat and soot problem, so see our guide on that.
The fragrance load is too low. Midwest says to test 6, 8 and 10 percent, with 10 only if your wax allows it.
The fragrance load is too high. Midwest notes that too much oil can clog the wick, cause weak or uneven hot throw, a struggling flame and sweating. Most waxes do best near 8 percent, it says, but check your wax's instructions. The Flaming Candle agrees that going past the limit "won't help".
The oil and wax do not get along. The Flaming Candle says some oils bond poorly with certain waxes, and that cheap or expired oil performs worse. NorthWood rates soy's throw as lower than paraffin's and coconut's, which is its own rating and not a test.
It was added at the wrong temperature or not mixed enough. The Flaming Candle names both. Neither page gives a number, so use the add and pour temperatures on your wax's sheet.
You are testing badly. Midwest points out that sitting in the room gives nose fatigue, so you stop smelling it. Its method is to light the candle, leave and close the door, but the National Candle Association says never to leave a burning candle unattended. So have someone stay with the flame while you wait outside, and come back every 1 to 2 hours to judge. If no one can watch it, put the candle out before you leave. Our fair scent test has the steps. Also, a small candle in a big room will always seem weak. Midwest suggests 4 to 9 oz for a small bathroom, 10 to 14 oz for a small or medium room and 16 oz or more for a medium room.
Worked example: a test grid
Say one wax and one oil, in a jar that holds 6 oz (170 g) of wax. You want to find the problem, so you pour six test candles: two wick sizes at three loads. The loads are percents of the wax. All numbers are examples.
| Load | Oil per candle | Two wicks |
|---|---|---|
| 6% | 6 x 0.06 = 0.36 oz (10 g) | 0.72 oz |
| 8% | 6 x 0.08 = 0.48 oz (14 g) | 0.96 oz |
| 10% | 6 x 0.10 = 0.60 oz (17 g) | 1.20 oz |
Total oil: 0.72 + 0.96 + 1.20 = 2.88 oz (82 g). Cure all six the same length of time, burn them side by side, and have someone else rank the scent without knowing which is which if you can. Keep the 10 percent candles only if your wax allows 10 percent. If the smell tracks the wick more than the load, the wick was your problem. If it tracks the load, the oil was.
Common mistakes
- Adding more oil first. It is the first reflex, and it can make things worse.
- Judging an uncured candle.
- Changing the wick, load and oil at the same time.
- Smelling the candle while sitting next to it for an hour.
- Using the same load for every oil, when dense oils may throw at lower loads (Midwest).
- Trusting a bottle's cold smell as a sign of hot throw.
Questions
Is a strong cold throw a sign of a strong hot throw?
No. Cold throw is the smell of the unlit candle and hot throw is the smell while burning. A good cold throw does not guarantee a good hot throw, so burn the candle. Our guide on the difference covers it.
Does the wax type change throw?
It can. NorthWood rates paraffin and coconut as excellent and soy as good, but that is a supplier's own rating. Your oil and wick matter as much, so test.
How long should I cure before judging scent?
At least a week for soy and blends, per The Flaming Candle, and longer if your wax sheet says so.
How BatchLab helps
The maker behind Ark & Dove built BatchLab for his own candle business. Burn testing keeps a record of every test candle, so you can write down the wick, load, cure time and what you smelled next to the recipe. Each batch keeps its fragrance load. It cannot smell the candle for you.
Sources
Reviewed .