Many candle makers face this common problem:
The candle smells strong and pleasant before lighting (cold throw), but once lit, the scent becomes very weak or almost not noticeable (hot throw).
Why does this happen?
Is it a fragrance problem?
Is it wax quality?
Is it wick size?
In this article, we will explain clearly the technical reasons behind weak scent throw and how to solve the problem step by step.
Understanding Cold Throw vs Hot Throw
Before solving the issue, we must understand two important terms:
- Cold Throw: The smell of the candle when it is not burning.
- Hot Throw: The smell released when the candle is burning.
A candle may have strong cold throw but weak hot throw. This is because scent release depends on heat and evaporation behaviour.
When the candle burns, fragrance molecules must evaporate properly into the air. If evaporation is not optimized, the scent will not spread effectively.
Reason 1: Fragrance Load Too Low
Fragrance load means the percentage of fragrance oil added into wax.
Typical fragrance load:
- Paraffin wax: 6% - 10%
- Soy wax: 6% - 12%
- Coconut wax: 8% - 12%
If fragrance percentage is too low, scent will not be strong enough during burning.
However, adding too much fragrance can also cause:
- Oil sweating
- Poor burning
- Wick drowning
It is advisable to do testing and always follow the recommended load for your wax type.
Reason 2: Incorrect Wick Size
Wick size controls heat output.
If wick is too small:
- Flame is weak
- Melt pool is shallow
- Wax does not melt fully
- Fragrance does not evaporate efficiently
If wick is too large:
- Candle burns too hot
- Fragrance may burn off too fast
- Scent becomes distorted
- Soot may form
Ideal condition:
The melt pool should reach near the container edge within 2-3 hours.
Proper wick testing is critical for strong hot throw.
Reason 3: Poor Wax and Fragrance Compatibility
Different waxes hold fragrance differently.
For example:
- Soy wax holds fragrance well but releases scent slower.
- Paraffin wax gives stronger hot throw.
- Coconut blends offer balanced performance.
Some waxes trap fragrance molecules too strongly and reduce evaporation when burning.
Testing different wax types or blends may improve hot throw significantly.
Reason 4: Improper Mixing Temperature
When adding fragrance into wax, temperature matters.
If added too hot:
- Fragrance may evaporate during mixing.
- Top notes may be lost.
If added too cold:
- Fragrance may not bind properly with wax.
General guideline:
- Add fragrance at 65-75°C (depending on wax type).
- Stir gently for 1-2 minutes for proper binding.
Good mixing improves scent distribution.
Reason 5: Curing Time Too Short
Curing is very important, especially for natural wax like soy.
Recommended curing time:
- Soy wax: 7-14 days
- Paraffin wax: 2-5 days
- Blended wax: 5-10 days
If candle is burned too soon after pouring:
- Fragrance may not fully bind with wax.
- Hot throw will be weak.
Patience improves performance.
Reason 6: Room Size Too Large
Sometimes the candle is not the problem. It might be due to:
- The room is too big
- Ceiling is high
- Ventilation is strong
- Fan or air-conditioner is running
The scent may dilute quickly.
Candle performance depends on room environment.
Test in a small enclosed space first to evaluate properly.
Reason 7: Fragrance Composition Matters
Some fragrance types naturally have weaker hot throw. For example:
- Light floral
- Green notes
- Citrus top notes
These evaporate quickly and may not last long.
Heavier notes such as:
- Vanilla
- Musk
- Amber
- Woody notes
Usually perform stronger in candles.
Blending fragrance with base notes improves hot throw stability.
How to Improve Hot Throw (Practical Solutions)
If your candle smells good when cold but weak when burning, try the following:
- Increase fragrance load slightly (within safe limit).
- Test a larger wick size.
- Adjust pouring temperature.
- Extend curing time.
- Test different wax blend.
- Use fragrance designed for candle.
- Check melt pool formation.
- Test in smaller room.
Make changes one variable at a time to identify the real cause.
Common Mistake: Adding Too Much Fragrance
Many beginners think "If smell is weak, just add more fragrance."
This is not always correct. Overloading fragrance can cause:
- Reduce burn quality
- Cause sweating
- Affect flame stability
- Lower scent performance
Proper formulation balance is more important than simply increasing dosage.
Technical Checklist for Strong Hot Throw
For reliable performance, ensure:
- Correct wax type
- Fragrance load within recommended %
- Proper mixing temperature
- Proper curing time
- Correct wick size
- Full melt pool formation
- Balanced fragrance composition
Strong hot throw is a result of correct formulation and testing.
Conclusion
If your candle smells good before lighting but weak when burning, the problem is usually related to:
- Wick size
- Fragrance load
- Wax type
- Curing time
- Mixing method
Hot throw depends on proper heat, evaporation and fragrance behaviour.
Candle making is both science and testing. Small adjustments in formulation can significantly improve scent performance.
When all components are balanced correctly, your candle should deliver both strong cold throw and strong hot throw, creating a satisfying experience for end users.
