Fragrance oils are made from a combination of synthetic chemicals and natural ingredients. Their chemical composition and formulation enable them to bind well in candle wax. If added at the right temperature, the chemical composition prevents the fragrance from dissipating during the candle making process. If added at too high of a temperature, the fragrance oil will dissipate in the hot wax and lead to an unscented candle. Fragrance oils are typically less expensive than essential oils and come in many different scents to choose from. Since fragrances oils are produced from synthetic chemicals, they can be consistently reproduced with a high degree of accuracy.
Essential oils are pure extracts derived from natural sources such as plants. They are characterized as therapeutic and are widely used in aromatherapy. There are several ways in which essential oils are extracted from their sources, such as steam distillation, enfleurage, and solvent extraction. Because of the essential oil extraction process and the large amount of plants required to extract enough essential oil from, they are typically more expensive than fragrance oils. Essential oils can be trickier to work with in candles due to quicker dissipation and not being chemically formulated to stabilize in melted wax. Essential oils can also vary depending on the environmental factors and extraction process, making it difficult to generate a consistent scent.