Essential Oils vs Fragrance Oils in Candles

What each one is

An essential oil is taken from the seeds, flowers, leaves, roots, stems or bark of a plant, usually by steam distillation or pressing. It smells like that plant and nothing else.

A fragrance oil is a blend. One candle supplier describes it as a mix of essential oils and synthetic aroma chemicals, designed for use in products like candles. That is how a maker can smell like fresh-baked cookies or a crackling fire, scents with no oil to extract. Some suppliers also sell “natural” fragrance oils made from natural and nature-identical ingredients.

Is “natural” safer or better?

The National Candle Association says candles made with natural ingredients are not necessarily safer than ones made with synthetic ingredients. What counts is that the ingredients are known to be safe and approved for candles, whether natural or man-made. So skip any claim that plant means safe, or that a man-made scent is harmful. What matters is how the finished candle burns.

Fragrance in any form can raise soot slightly, according to the same association, but it says wick length and flame disturbance are the main drivers. Trim wicks to ¼ inch and keep candles out of drafts either way.

Why essential oils are harder in wax

• Flash points. Many essential oils ignite at lower temperatures than fragrance oils. Citrus oils such as lemon, orange and grapefruit are the usual troublemakers. One supplier’s lab suggests avoiding essential oils with a flash point under 170°F. Another says to cool wax to about 10°C under the oil’s flash point before adding it. Read each oil’s safety data sheet. Flash point is a safety measure, not a recipe by itself; see when to add fragrance oil.
• Performance varies. Essential oils were not designed for candles. Some hold their scent through a burn, and others fade or behave unpredictably in certain waxes.
• One note only. A single essential oil is a single plant’s scent. For depth you blend several, which costs more.
• They age quickly. One supplier says to refrigerate essential oils in airtight containers and use them within 6–12 months, while fragrance oils are stored at room temperature and used within about a year. See fragrance oil shelf life.

One supplier tested several essential oils in its own wax and reported that French lavender, patchouli, Egyptian geranium, ylang ylang and cedarwood did well, with patchouli giving a slight yellow tint and cedarwood a little yellowing. That is one lab, one wax and one set of wicks. Use it as a short list to test, not a promise.

How much to use

Weigh essential oils like any other candle oil, as a percentage of the wax weight. One supplier’s starting points for essential oils are 6–10% in soy and coconut waxes, up to 12% in paraffin, and 3–6% in beeswax. Another suggests testing below 10%. These are only places to begin, and your wax maker’s limit still applies. Follow how much fragrance oil to use.

A fair side-by-side test

The only way to know is to pour both. Make two testers from the same batch of wax, with the same jar, wick, dye and load, changing only the oil. Weigh the oils so the loads match. Let both cure for the same time, store them together, and burn them in the same room on the same day. Judge the unlit scent first, then the scent while burning, and write down which one you would sell. An essential oil that is lovely in the bottle can fade in the melt pool, and the reverse is just as possible.

Suppliers say essential oils suit makers who want a plant-only scent. Be ready for more testing and a smaller range of scents. Fragrance oils give you more scents and, from supplier reports, steadier performance.

How to choose for your candle

1. Check the product page. Does it say the oil is for candles?
2. For an essential oil, find its flash point on the safety data sheet and check supplier notes for wax testing.
3. Check your wax’s fragrance limit and the oil’s IFRA certificate if one is supplied.
4. Pour a small test candle. Change only the oil, so you are comparing like with like.
5. Complete the full burn test and judge scent after the wax’s cure time, as described in candle cure time.