Soy wax production
Soy wax is produced form soybean oil but may contain other non-soy ingredients. Soybean oil is separated from the solid components by solvent extraction or by mechanical pressing. This raw oil will be further refined and bleached. About 60 kg of soybeans are required to produce 10 kg of soybean oil. The soy solids, which remain after oil extraction, can be used as cattle feed. To make the soybean oil more solid (to make wax of it) it is hydrogenated.
Hydrogenation of soybean oil
The exact steps to produce soy wax are well protected and every producer may have his own secrets. The main step in making soy wax is hydrogenation. Hydrogenation is the process whereby the poly- and monounsaturated oils are solidified in order to increase the viscosity. This is done by reaction of hydrogen with the oil at elevated temperature (140-225°C) in the presence of a nickel catalyst.
It is important to stir the mixture to help dissolve the hydrogen and to achieve a uniform distribution of the catalyst with the oil. The hydrogenation process will create saturated fats (the double bonds are converted into single bonds) which are not very healthy forhuman consumption because the contain trans-fats!. However, for making soy candles or soy wax this is not a problem.
Other ingredients of soy wax
Hydrogenation of soybean oil alone will produce a wax with low melting point and not so solid texture. This type 100% soy wax may be suitable for container candles but not for pillar candles. Other ingredients, such as paraffin or stearic acid, need to be added to produce solid wax for votive candles. Many soy candles shops sell their pillar candle wax as "blended wax" and not as "soy wax." Fragrance oils and dyes are often added to soy candles. Scented soy wax, which is very popular, can contain up to 10% fragrance oil, which are readily miscible with wax. Often dyes are incorporated in scented soy wax, for example green dye in apple flavoured wax or purple dye in blueberry flavoured wax.
There are no regulations about the composition of soy wax. If you want to be sure that your soy candles are 100% soy, you will have to ask your supplier!