Cold Throw & Hot Throw in Scented Candles: Why Candles Smell Different When Cold and Hot

Fragrance oils can smell significantly different in a finished candle than directly from the bottle.

The reason is simple:

In a candle, the fragrance composition is no longer a free liquid but part of a complex system of wax, wick, and temperature.

Therefore, in candle making, a distinction is often made between Cold Throw and Hot Throw.

Brief explanation

Cold Throw = Scent perception of a cold, unlit candle.

Hot Throw = Scent effect while burning.

A strong Cold Throw does not guarantee a strong Hot Throw.

What does Cold Throw mean?

Cold Throw describes how intensely and characteristically a candle smells when it's cold.

It is particularly important for the initial customer impression.

When a customer:

• opens the lid
• smells the candle in a store
• smells it immediately after unpacking,

they experience the Cold Throw.

The fragrance molecules must travel from the solid wax surface into the ambient air.

What does Hot Throw mean?

When burning, a liquid melt pool forms.

The higher temperature changes the mobility and evaporation of the fragrance components. Simultaneously, rising warm air currents carry volatile components into the room.

Therefore, Hot Throw is not simply a stronger Cold Throw, but a different operating situation for the candle.

Why does fragrance oil smell stronger from the bottle?

In the bottle, the fragrance composition is highly concentrated and liquid.

In a candle, it is dispersed within the wax structure.

Fragrance release is therefore influenced by:

• wax type
• temperature
• fragrance concentration
• surface area

among other factors.

Precisely for this reason, a candle fragrance should never be evaluated solely from the bottle.

What role does the wax play?

Wax is not simply a neutral container.

Different wax systems have different:

• melting ranges
• crystal structures
• hardness
• processing properties
• fragrance tolerances.

Professional wax manufacturers therefore offer different products for container candles, pillar candles, wax melts, and other applications.

What role does the wick play?

The wick influences:

• flame height
• melt pool size
• heat input
• evaporation conditions.

Therefore, a wick suitable for an unscented candle is not automatically optimal for the same candle with a high fragrance load.

Cargill explicitly names wax, vessel diameter, and fragrance amount as factors in wick selection.

Does more fragrance oil help with weak Hot Throw?

Not automatically.

While increasing the amount of fragrance can improve the scent effect in some systems, too high concentrations can worsen burning behavior or lead to separation.

If the Hot Throw is weak, the following should therefore be checked simultaneously:

• fragrance concentration
• wax
• wick
• vessel
• melt pool
• manufacturing conditions
• cure time.

Why does a candle need cure time?

After pouring, the wax continues to crystallize or structure itself during cooling and storage.

The optimal time until testing depends on the specific wax system.

Therefore, the wax manufacturer's recommendation should be considered, and the same cure time should always be used for development trials.

Professional Test Plan

1. Bottle evaluation

Note:

• character
• intensity
• dominant notes.

2. Produce a standardized test candle

Do not change several variables simultaneously.

3. Evaluate Cold Throw

For example:

• after 24 hours
• after a few days
• at the intended final test time.

4. Conduct burn test

During burning, document:

• Hot Throw
• flame height
• melt pool
• soot formation
• burn time.

5. Standardize the testing environment

For comparable results, ideally use:

• the same room
• the same candle position
• similar room temperature
• same burn duration

when possible.

If possible, several people should independently evaluate the scent intensity.

Why the same fragrance composition can smell different cold and warm

A fragrance composition contains substances with different physical and sensory properties.

Upon heating, the release dynamics change.

As a result, certain fragrance facets can:

• become more prominent
• appear weaker
• be perceived earlier or later.

This is not a quality defect.

It is a normal part of fragrance development in a thermally operated system.

FAQ

What is more important – Cold Throw or Hot Throw?

For a high-quality scented candle, both are important.

Why is my Cold Throw strong, but the Hot Throw weak?

Possible causes include wick, wax, fragrance amount, or a non-optimal melt pool.

Can a different wick improve the Hot Throw?

Yes. Since the wick influences heat input and the melt pool, a different dimensioning can alter the fragrance release.

Which wax has the best Hot Throw?

There is no universal winner. The specific wax must be tested with the fragrance composition.

Can I judge fragrance oil directly from the bottle?

For pre-selection, yes. For the final evaluation of a candle, no.

Conclusion

Cold Throw and Hot Throw are the result of the entire candle system.

Fragrance + Wax + Wick + Vessel + Temperature + Time

jointly determine how a scented candle is perceived.

Professional scented candle development therefore always means:

test – document – compare – optimize.

Reviewed by: Aroma Nova Product Development
Date: August 2026

Technical Sources

Cargill NatureWax – technical notes on wax, fragrance load, wick, and processing.