How much fragrance oil to add to candles: fragrance load, temperature and curing

TUREFF• •0

A candle that looks lovely but smells of nothing is one of the most common disappointments for new makers. Scent depends on how much fragrance you add, when you add it and how long you let the candle cure. More is not always better: too much fragrance can make a candle burn badly or unsafely.

What fragrance load means

Fragrance load is the amount of fragrance oil as a percentage of the wax, measured by weight, not volume. For example, 1,000 g of wax at 8% takes 80 g of fragrance oil. Some makers instead calculate the percentage of the total (wax plus oil). Both methods are in use, so check which one your supplier's guidance assumes.

Typical ranges

Many container waxes, including common soy waxes, are used at somewhere around 6% to 10%, and some waxes are rated to take more. Every wax has its own maximum fragrance load set by the manufacturer, and every fragrance oil has its own recommended use rate. Follow your wax supplier's guidance and never exceed the stated maximum. Why not just add more?

Wax can only hold so much oil. Excess oil can seep out to the surface (sweating) or pool at the bottom.
Overloaded candles can burn with larger flames, more soot, or struggle to stay alight.
Fragrance oils are often the part of a candle with the most safety considerations, so loading more also increases what you need to label if you sell.

Many makers find a moderate load, well chosen, smells stronger than a maximum load of a weak fragrance. Test a few percentages side by side.

Use oils made for candles

Use fragrance oils sold for candle making, with a safety data sheet (SDS) available from the supplier. Check the oil's flash point and the supplier's guidance on candle use. Not every fragrance or essential oil is suitable for burning.

When to add fragrance

Fragrance is added to melted wax, not to wax that is still solid or already cooling. Many suppliers suggest a temperature around 185°F (85°C) for adding fragrance to many waxes, but recommended temperatures differ between waxes, so use the figure your supplier gives.

Too cool, and the oil may not bind properly with the wax.
Too hot, and you risk losing some of the lighter notes and getting close to the flash point of some oils.

Stir gently but thoroughly for a couple of minutes after adding fragrance, so the oil binds evenly. Stir slowly to avoid air bubbles.

Pouring temperature

After adding fragrance, let the wax cool to its recommended pouring temperature before pouring. Pouring too hot or too cold affects the surface, adhesion to the jar and how well the scent stays in.

Curing

Curing is the time between pouring and burning, during which the wax and fragrance settle and the scent develops. Soy and other natural waxes are usually given longer than paraffin. Many makers leave soy candles a week or two, though supplier guidance varies, and some find their candles keep improving for longer. Cure candles at room temperature, away from sunlight, with a lid or cover to keep dust off.

Cold throw and hot throw

Cold throw: how the candle smells unlit.
Hot throw: how it fills a room when burning.

A strong cold throw does not guarantee a strong hot throw. Test the hot throw by burning the candle in a closed room of reasonable size, leaving the room for a while, and noticing the scent when you come back in.

When the scent is weak

Check you measured by weight and calculated correctly.
Try a longer cure.
Check the wick: an undersized wick makes a small melt pool and releases little scent.
Try a different fragrance oil; some perform better in certain waxes.
Only then consider raising the load, staying within the maximum.

Keep records

Note the wax, oil, percentage, temperatures, wick and cure time for every test. Change one thing at a time so you know what made the difference. What fragrance load works for your wax? Share your results or ask questions in the comments.