Candle Fragrance Load Explained: How Much Oil Should You Use?

1. What is fragrance load (and why it matters)

Definition: Fragrance load is the ratio (by weight) of fragrance oil added to the candle wax. For example, if you have 100 g of wax and you add 8 g of fragrance oil, the fragrance load is 8%.

This is distinct from “fragrance content” (which sometimes is expressed as % of the finished candle weight).

Why it matters: 

• The wax can only hold a certain amount of oil before structural or performance issues arise (bleeding, oil‐seepage, weak burn, excessive sooting).
• Fragrance load affects both cold throw (the scent you smell when candle is unlit) and hot throw (when candle is burning). Too little oil = weak scent. Too much can degrade wick performance, melt pool control, and create safety issues.
• Achieving a consistent load is key for repeatable produ ct quality, especially in small-batch or professional candle manufacturing.

2. How wax chemistry and wax type affect fragrance load

Different waxes (soy, coconut, paraffin, blends) have differing capacities to hold fragrance oils, due to differences in molecular structure, melt point, viscosity, crystallisation behaviour, adhesion to containers, etc.

A guideline for soy waxes is generally of ~6-10% for optimal performance. Because soy wax tends to have a lower melt point and specific crystallisation behaviour, a high fragrance load may more easily cause migration or wet-spots in containers. Example: AAK “Golden Wax 464” (soy container wax) specifies a maximum fragrance load of around 10 %, with some suggestions starting at 6 % for best results.

Generally, other natural waxes like coconut or olive blends are considered higher perfume load capable ( up to 12%). Example: Kerax Olive™ Pillar Wax (olive + natural additives) states it can take up to 12 % fragrance load. 

For paraffin and blends the capacity tends to vary, but many sources suggest 8-12% for certain blends. However, volume, burn performance and wick sizing may limit practical fragrance load even if technically possible.

There is no one-size-fits-all number. The maximum feasible fragrance load depends on: wax formulation, container size/shape, wick choice, fragrance oil properties (density, compatibility), curing time, pour temperature, etc. Always follow the wax manufacturer guidelines as starting point. At our website you can find those in the Properties table on each of the waxes pages.

3. Step-by-step calculation and labeling of fragrance load

A. Basic formula

Weight of fragrance oil, g = Total weight of the finished candle (wax + FO), g X (desired fragrance load, % : 100)

(Ensure you are using weights, not volumes) 

and then,

Weight of wax, g = Total weight of the finished candle (wax + FO), g - Weight of fragrance oil, g 

B. Example calculation

You plan to make a 200 g candle at 8% FO (of total weight)

• F (Weight of fragrance oil, g) = 200 X (8:100) = 16 g
• W (Weight of wax, g) = 200−16 = 184 g

This version is easier for beginners to use:

1. Choose the total candle weight.
2. Multiply by the desired % to get fragrance oil.
3. Subtract to get the wax.

Practical tip for manufacturing

• Always round weights to 1 decimal or nearest gram depending on batch size.
• Keep a log of fragrance load, wax melted, pour temperature, wick size, cure time — to correlate with performance.
• For multi-sku products: maintain a “standard fragrance load” (e.g., 8%) but test each fragrance oil individually (see section 5)
• Even if your wax manufacturer says “up to 10%”, you may need to reduce fragrance load due to process/production factors. Below are critical variables:

4. Practical process factors affecting how much fragrance oil you can safely use

• Some fragrance oils are heavier, have higher flash points or include additives that don’t mix well with wax. Example: adding fragrance when wax is too hot can cause fragrance loss or migration.
• If fragrance is “dense” (e.g., base-notes like patchouli/oud) it may depress wax melt point or increase sooting at higher load.
• Pouring too cool or too hot influences adhesion, sink-holes, frosting, and may require reducing fragrance load. For example, AAK Golden Wax 464 (EU) suggests pour at 55-65 °C.
• Slow cooling is beneficial for adhesion; rapid cooling may cause “wet spots” or separation if fragrance load is high.
• A higher fragrance load increases volatility of hot throw but also increases demand on wick to deliver enough heat. If wick cannot support it, you may get tunnelling, incomplete melt pool or low scent throw.
• Some sources suggest heavier waxes or higher fragrance loads require larger wick sizes.

Container size, shape and ventilation

Larger containers require stronger hot throw, which may mean higher fragrance load or more efficient wax/fragrance combination. But with larger volume, wax may melt more slowly and fragrance may be less efficiently diffused, so even if load is increased, effect may not scale linearly.

Curing time

Fragrance dispersion and binding into wax matrix takes time; insufficient cure may make even correct fragrance load perform weakly. (See section 6) High fragrance load may show more bleeding or migration if cure is insufficient.

Ingredient interactions (colourants, additives, wax blends)

• Colour dyes may absorb or react with fragrance oils, affecting throw.
• Additives (e.g., stearic acid, wax boosters) may alter maximum safe fragrance load.
• If you blend waxes (e.g., soy + paraffin), the safe fragrance load may change.

5. Testing, curing and optimisation of fragrance load

A. Batch testing methodology

1. Select your wax and fragrance oil.
2. Determine a baseline fragrance load (e.g., 6% for soy).
3. Make small test batches at different loads (e.g., 6 %, 8 %, 10 %).
4. Use same container, same wick size, same pouring and curing conditions.
5. Measure cold throw (after solidified), hot throw (after burn pool establishment), visual finish, melt pool size, wick behaviour, any oil separation or wick clogging.
6. Note results and choose optimum load for that oil/wax combination.

B. Curing time

• For AAK 464 soy wax, one test indicated 2 weeks cure time for optimal scent throw.
• For coconut/soy blends say at least 48 h but up to 1–2 weeks is beneficial for hot throw.
• Insufficient curing may make your product underperform even if fragrance load is within spec.

C. Visual / performance checkpoints

• On first burn, look for full melt pool, no tunnelling, flame stability.
• Smell strength: cold throw in unlit environment, hot throw in standard sized room.
• Surface appearance: no wet spots, frosting, or bloom (especially for soy wax)
• Burn time: Ensure fragrance load hasn’t significantly reduced expected burn hours.
• Customer feedback: Does the scent last / fade too quickly.

D. Optimisation decisions

• If performance at baseline is weak: increase fragrance load in small increments (e.g., +1 %) and retest.
• If you reach manufacturer maximum load (e.g., 10 %) and still weak throw: consider switching wax or oil, or optimise wick / container size.
• If you observe negative effects (sooting, oil seepage, wet spots): reduce fragrance load.

6. Trouble-shooting: common issues when fragrance load is too high or too low

A. Too low fragrance load

Symptoms may include:

• Weak cold throw and/or hot throw (customers comment “I can’t smell it”).
• Candle may burn fine but lacks appeal.

Solution: incrementally increase fragrance load, retest; check that fragrance oil is quality and compatible.

B. Too high fragrance load

Symptoms may include:

• Oily film on surface, wax separation or oil pooling on top of candle.
• Sooting, large flame, erratic burn, wick carbon build-up, wax sucking down around wick.
• Wet spots (especially in glass containers) or poor adhesion/detachment of wax from container.
• Shortened burn time, unstable flame.

Solution: reduce fragrance load; ensure correct wick size; check pour/cure parameters; ensure fragrance oil flash point is higher than pour/solidification temperature; test compatibility of fragrance oil with wax.

7. Commercial / regulatory considerations for fragrance load

• For commercial production, you must document fragrance load, testing results, burn time, safety data, component declarations.
• For example, fragrance calculators provide weighting and regulatory guidance for CLP/IFRA compliance.
• Pricing: fragrance oils are more expensive per gram than wax; using higher load increases cost per candle, so optimum may balance cost vs performance.
• Labelling: Some jurisdictions require naming fragrance oils or stating “contains fragrance oil” and ensuring safe burn performance.
• Batch records: It's advisable to keep records of wax batch, fragrance lot, load %, oven/ pour temperatures, cure time, burn test results for traceability and quality assurance.

8. Summary checklist for candle makers

• Choose your wax and note manufacturer’s recommended fragrance load (and maximum).
• Use the fragrance load formula: 

Weight of fragrance oil, g = Total weight of the finished candle (wax + FO), g X (desired fragrance load, % : 100)

Weight of wax, g = Total weight of the finished candle (wax + FO), g - Weight of fragrance oil, g

• Select initial fragrance load (start lower than max, e.g., soy = ~6 %).
• Weigh everything accurately (digital scale).
• Melt wax to recommended temperature, add fragrance oil at correct temp, stir thoroughly.
• Pour at correct temperature into pre‐conditioned container.
• Cure candles for recommended time (e.g., 48 h to 2 weeks depending on wax).
• Test burn and evaluate: cold throw, hot throw, melt pool, surface finish, wick behaviour.
• Adjust fragrance load upward or downward as needed based on test results.
• Document batch metrics and ensure regulatory compliance.
• For each new fragrance oil or wax lot, repeat testing – never assume results will match previous loads exactly.