Candle making process. Source: Wikimedia Commons
Fragrance work in candle making involves two distinct problems: the technical problem of getting fragrance oil to bind correctly with the wax without separation or seepage, and the sensory problem of creating a scent that performs well both at room temperature (cold throw) and when the candle is burning (hot throw). These two goals are not always achieved by the same formula.
Fragrance load
Fragrance load refers to the percentage of fragrance oil by weight relative to the total wax weight. A candle made with 100g of soy wax and 8g of fragrance oil has an 8% fragrance load.
Recommended ranges by wax type
| Wax type | Minimum usable load | Typical working range | Maximum before seepage |
|---|---|---|---|
| Container soy wax | 4% | 6–8% | 10–12% |
| Coconut wax | 4% | 7–10% | 12% |
| Beeswax | 2% | 3–5% | 6–7% |
| Soy/coconut blend (70/30) | 5% | 7–9% | 11% |
Seepage occurs when the wax cannot absorb the full quantity of fragrance oil — excess oil separates out and pools on the surface or beneath the wax. This happens at high load percentages but also when fragrance is added at too low a temperature, when the wax is poured too quickly, or when the specific fragrance oil has a low viscosity.
Flash point and temperature
Every fragrance oil has a flash point — the temperature at which its vapour can ignite when exposed to a flame. Flash point is not a direct indicator of fragrance quality, but it is relevant for two reasons in candle making:
- Safety: Fragrance should be added to melted wax at a temperature below the oil's flash point to avoid fire risk. Most candle-grade fragrance oils have flash points above 65°C, but some botanical essential oils have flash points as low as 50°C.
- Binding: Adding fragrance at too high a temperature causes lighter volatile compounds to evaporate before the wax sets, reducing the finished candle's scent intensity. Adding at too low a temperature (below the wax's binding temperature) can result in fragrance not fully incorporating.
Working temperature for fragrance addition: For container soy wax, the generally used temperature range for adding fragrance is 60–65°C — after the wax has melted fully and cooled slightly from its maximum temperature. The wax should then be stirred consistently for at least two minutes before pouring. This is a general guideline; specific wax and fragrance combinations should be tested.
Scent structure: top, middle, and base notes
Fragrance notes describe how a scent's character changes over time. In perfumery, this refers to what is perceived immediately after application (top notes), after a few minutes (middle notes), and as the base scent after extended wear (base notes). In candle fragrance blending, the concept applies differently because the scent is continuously volatilised by heat rather than applied to skin.
Top notes in candles
Top notes in candles are most prominent in the cold throw and in the first minutes of burning. Common top note materials in candle fragrance oils include citrus (bergamot, lemon, orange), light herbal (eucalyptus, peppermint), and green notes (fresh grass, cucumber). These compounds are volatile and tend to diminish in intensity in the hot throw, particularly in candles with long burn times.
Middle notes
Middle notes form the core character of the scent and are most prominent during active burning. Floral notes (rose, jasmine, geranium), spice notes (cinnamon, clove, cardamom), and light wood notes (cedar, sandalwood) are frequently used as candle middle note components. They are less volatile than top notes and remain detectable for the duration of the burn.
Base notes
Base notes are the slowest to volatilise and define the scent's warmth and staying power. Common base note materials in candle fragrance include musk, vanilla, amber, patchouli, vetiver, and tobacco. Heavy base note compositions are well-suited to beeswax, which has a lower absorption capacity for lighter volatile compounds.
Blending ratios
A structurally balanced candle fragrance typically uses a blend of all three note categories. A common starting ratio for a simple three-component blend is:
- 20–30% top notes
- 40–50% middle notes
- 20–30% base notes
These proportions are starting points for testing — the actual ratio depends on the specific fragrance materials used, the wax's absorption profile, and the intended character of the finished scent.
Single-fragrance versus blended compositions
Not all candle fragrances are multi-component blends. Many candle makers use single fragrance oils purchased from wholesale suppliers, which are themselves pre-blended compositions formulated for candle use. Working with pre-blended oils removes the complexity of note balancing but limits customisation.
Custom blending allows a maker to adjust a scent to perform better in a specific wax or to differentiate their product. It also introduces more variables into the testing process — each change in blend ratio requires a new burn test cycle.
Essential oils versus synthetic fragrance oils
Essential oils are natural plant extracts. Many have lower flash points than synthetic fragrance oils and a narrower range of workable temperatures. Some essential oils — particularly citrus and conifer oils — dissipate quickly at candle temperatures and produce minimal hot throw. Eucalyptus, clove, and cinnamon essential oils are more stable at candle temperatures and perform reasonably as hot throw contributors.
Synthetic fragrance oils are formulated to remain stable across a wider temperature range and are designed for candle use. Most candle fragrance suppliers provide technical data sheets that specify flash point, recommended usage rate, and compatibility with different wax types.
Candle surface detail. Source: Wikimedia Commons
Fragrance testing
Because hot throw can only be evaluated through burning, fragrance testing requires at least two to three complete burn cycles per formula. The first burn establishes the initial melt pool; subsequent burns reveal how the scent intensity changes as the wax level drops and the heat reflected from the container walls increases.
Cold throw testing can be done more quickly by making small wax discs or tarts — thin flat portions of the wax mixture that cool within an hour and can be assessed without burning. Cold throw strength from a disc does not directly predict hot throw strength, but it indicates whether the fragrance oil has bonded with the wax.
Fragrance load percentages and working temperatures mentioned here are general references. Always check the fragrance supplier's technical data sheet for flash point and recommended usage rate before working with a specific oil. Handling concentrated fragrance oils requires skin protection and adequate ventilation.
Updated: June 2026 · References: Wikipedia — Fragrance oil · Wikipedia — Perfumery notes