Stearic Acid: Uses in Candles, Soap and Cosmetics

Stearic acid is a saturated fatty acid with an 18-carbon chain. It occurs naturally in vegetable oils such as palm and in animal fats, and the commercial product is made by splitting and refining these fats. It comes as white, waxy flakes, beads or powder with a faint fatty smell. In Hindi it is written स्टीयरिक एसिड.

• Formula: C18H36O2
• CAS number: 57-11-4
• Molar mass: about 284.5 g/mol
• Melting point: about 69 °C
• Solubility: practically insoluble in water; dissolves in hot alcohol and in melted oils and waxes

Because it is solid at room temperature but melts below the boiling point of water, it blends easily into melted waxes and fats and makes them harder once cooled.

We sell stearic acid in three listings. The material is similar; the difference is form and pack.

Flakes are easier to weigh for candles; powder melts a little faster in small cosmetic batches. Check today's price per kg before ordering.

• Candles: added to paraffin wax to make candles harder and more opaque, help them release from moulds, and slow dripping.
• Soap: gives cold-process and melt-and-pour bars extra hardness and a creamier lather.
• Cosmetics: thickener and co-emulsifier in creams, lotions, shaving creams and body butters.
• Industry: rubber processing, lubricants and greases, plastics, and making metal stearates and other derivatives.

1. Paraffin candles: a common starting point is about 10% stearic acid by weight of wax, so 100 g for every 1 kg of paraffin. Melt the wax in a double boiler, add the flakes, and stir until fully clear. Pour at the temperature your wax supplier recommends.
2. Soy and other natural waxes: many don't need it. Test a small batch first, as it can change the look of the top.
3. Lotions and creams: usually 2 to 5% of the total weight. Melt it with the oil phase at around 70 to 75 °C, then add the heated water phase with your emulsifier and stir until it cools. More stearic acid gives a thicker cream.
4. Cold-process soap: stearic acid reacts with lye like any other fat, so include it in your recipe and run the whole recipe through a lye calculator. Don't add it on top of a finished recipe.

Always weigh, never measure by spoons. Flakes and powder take up very different volumes for the same weight.

• Handle the powder gently to avoid dust; a dust mask helps when weighing large amounts.
• Melted stearic acid and hot wax burn skin. Use a double boiler, never a direct flame, and keep a lid nearby for fat fires. Never pour water on burning wax.
• Keep away from strong oxidisers and strong bases except when used deliberately in soap making.
• Store sealed in a cool, dry place away from heat and sunlight. Over long storage it can pick up a stale smell.
• Keep away from children.
• Scrape cooled spills and put them in normal waste; don't wash melted wax down a drain, where it will set solid.

For candles and craft work, the 500 g flakes are the practical choice. One pack covers about 5 kg of paraffin at the 10% rate. For creams and lotions, the 250 g powder or cosmetic listing is enough for many small batches, since you use only a few grams each time.

Small soap and candle businesses usually buy several packs at once. If you use more than that every month, or need 25 kg bags, send us a bulk inquiry for a quote.