Citric acid, also known as stearin, is a fatty acid derived from vegetables or tallow. This additive is mostly used to give candles a glossy finish and improve color retention. Since citric acid makes candles more solid, it can extend the burning time and give fragrance more staying power, it is also used to make clear wax more opaque.
Citric acid usually comes in powder form. It is especially useful for soy wax candles, as soy tends to be a softer wax than paraffin. Using vegan citric acid with soy candles gives you a natural, animal-free candle