The most common complaint about scented candles is simple: “I can’t smell it when it’s lit.” Nine times out of ten, the problem is not the amount of fragrance but the match between the fragrance, the wax, the wick and the process. Here is how candle fragrance oil works, and what to ask before you buy it.
What is candle fragrance oil?
Candle fragrance oil is a fragrance formulated to dissolve in wax and release its scent both cold and when burning. It is designed for candle use specifically, with the right solubility, strength and stability in wax, and to IFRA Standards for candles, so it throws well without causing sooting, sweating or discolouration.
Perfume will not work: its alcohol evaporates and can be a fire hazard. Many essential oils work poorly too, being too volatile or too weak in wax. See fragrance oil vs essential oil.
Fragrance load: how much to use
Fragrance load is the percentage of fragrance oil in the wax by weight.
- Many candle waxes are commonly used at around 6–10% fragrance load.
- Each wax has a maximum it can hold, often stated by the wax supplier.
- More is not always better. Overloading can cause oil to “sweat” out of the wax, poor burning and soot, without improving throw.
Always check two limits: the wax manufacturer’s maximum load, and the maximum use level on the fragrance’s IFRA certificate for candles. Use the lower of the two.
Hot throw vs cold throw
| Cold throw | Hot throw | |
|---|---|---|
| What it is | Scent of the unlit candle | Scent released while burning |
| Matters for | The in-store sniff test | The customer’s experience at home |
| Driven by | Fragrance strength and lighter notes | Melt pool, wick, wax and fragrance design |
A good candle needs both. Strong cold throw and weak hot throw is the most common sign of a poorly matched fragrance or wick.
When and how to add fragrance
- Melt the wax fully to the supplier’s recommended temperature.
- Let it cool to the recommended fragrance-addition temperature (often around 80–85°C for many waxes, but follow your wax supplier).
- Add the weighed fragrance oil and stir gently but thoroughly for a couple of minutes so it binds with the wax.
- Pour at the recommended pouring temperature.
- Cure before testing or selling, typically one to two weeks for many soy and blended waxes, so the fragrance fully integrates.
Flash point, explained
The flash point is the lowest temperature at which a fragrance’s vapour can ignite in the presence of a flame. It is a safety and shipping figure on the safety data sheet. It is not the temperature at which the fragrance “burns off”. Fragrance added below or above its flash point does not lose its scent simply because of that number. What matters for performance is the addition temperature and good mixing.
Developing candles for your brand?
Common problems and fixes
- Weak hot throw: test a different wick size, check the load, extend curing, or use a fragrance designed for your wax.
- Sweating (oil on the surface): the load is too high for the wax, or the fragrance was added too cool or not mixed well.
- Soot and mushrooming wicks: often an oversized wick or too much fragrance.
- Discolouration: some materials, like vanillin, yellow or brown over time. Choose stable fragrances, or use colour to hide it.
- Frosting and wet spots: mostly a wax and temperature issue, especially with soy.
What to ask a supplier
- Is this fragrance designed and tested for my wax type (soy, paraffin, coconut, blends)?
- What is the maximum use level on the IFRA certificate for candles?
- Can you provide a safety data sheet and allergen information?
- Will the batch be consistent when I reorder?
- Can you match a reference scent or develop an exclusive one?
Frequently asked questions
How much fragrance oil should I add to a candle?
Many candles use around 6–10% fragrance oil by weight of wax. Never exceed the wax supplier’s maximum or the IFRA limit for candles on the fragrance certificate.
Which fragrance oil is best for candles?
One designed and tested for your specific wax, with strong hot throw, good stability and an IFRA certificate covering candles.
Why can’t I smell my candle when it is lit?
Usually the wick is too small, the candle was not cured long enough, the fragrance is not suited to the wax, or the room is too large for the candle.
Can I use essential oils in candles?
Yes, but many give weak hot throw and some are expensive at the levels needed. Blends designed for candles usually perform better.
Does Sawai supply candle fragrance oils?
Yes. We develop air care fragrances, including candle fragrances, for brands and manufacturers. Get in touch to discuss your wax and requirements.
Candle fragrances built to throw
Sawai develops candle and home fragrances tested for performance in wax, with consistent batches for brands that need to scale.
