Soy wax: how it is made, its properties, and what the claims are worth

What is soy wax?

Soy wax does not exist as such in nature: it is made from soybean oil, which is transformed by hydrogenation. This reaction adds hydrogen to the fatty acids in the oil; it changes their structure and makes the oil solid at room temperature. The resulting wax consists mainly of stearic acid, which gives it a soft, creamy texture somewhat reminiscent of cocoa butter.

It spread mainly from the 1990s, when an American manufacturer, Michael Richards, developed formulas for candles. Dates vary between sources (1991 to 1996 according to the documents), so we simply say “early 1990s.”

Physical properties

Its melting point is lower than that of other waxes, which is why soy candles are almost always sold in a jar or another container: the melted wax stays in place without running.

Common defects, and what they do not tell you

• Frosting: a white, crystalline film appears on the surface or on the glass. It is a normal recrystallisation, harmless but unsightly.
• Lifting spots (wet spots): the wax pulls away from the glass in places and leaves dark areas. This is cosmetic, not dangerous.
• Uneven surface after several burns, or small holes: consequences of cooling, which manufacturers correct by adjusting the pouring temperature.
• Scent throw: soy wax has a reputation for releasing fragrance less well when cold than paraffin; formulas vary widely.

These defects do not indicate poor quality in themselves; they are characteristics of the material.

What the science says about “burns cleaner”

Soy candles are often presented as “cleaner” than paraffin ones. The reality is more nuanced. A French study led by Ineris and CSTB (the EBENE project, 2017) measured the emissions of nine scented candles sold in France: their emissions differ greatly from one product to another. The published summary does not rank candles by type of wax; it is also known that the wick, the fragrance and how the candle is used play a role. Candles emit fewer particles than incense, but more nitrogen oxides, and their pollutants can remain in the air after the flame goes out. To our knowledge, there is therefore no solid basis for calling one wax “healthy” and another “toxic”; describing soy wax as “cleaner” remains a seller’s claim rather than an established fact.

The official advice is the same for all candles: use in moderation, ventilate the room, trim the wick to about 5 mm, and keep vulnerable people away. See Candle wicks.

Ecological issues

• Origin of the soy: much of it comes from the Americas, where soy expansion is linked to deforestation (Amazon, Cerrado), mainly for animal feed. The share going to candles is tiny, but the link exists. Look for an origin statement or a sustainability certification.
• GMOs: most soy grown in the United States is genetically modified. Some manufacturers offer “non-GMO” soy; the claim should be verified.
• Blends: a “soy” candle often contains other waxes (coconut, palm, paraffin); the law does not always require the proportion to be stated. Read the label.
• Biodegradability: a plant wax breaks down more easily than a mineral wax, but a glass or metal jar still needs to be sorted for recycling.

How to choose and use it

1. Check the composition: percentage of soy, presence of other waxes, nature of the fragrance.
2. Look at the wick (cotton, wood); see Candle wicks.
3. First burn: let the wax melt across the whole surface (usually one to four hours) to avoid tunnelling.
4. Trim the wick, avoid draughts, and extinguish the candle before the wax in the jar runs out.
5. Apply the rules in Fire safety and rituals.

If you are allergic to soy, ask a doctor for advice: hydrogenated wax contains very little protein, but added fragrances can pose problems. For the symbolism of candle colours, see Candle colours and symbolism.

Frequently asked questions

Also read

The meanings mentioned belong to tradition and symbolism. They are neither promises of results nor medical advice. Back to Herbs, waxes and accessories.