Many raw perfume materials are simply too strong, too irritating, or too unpleasant on their own to use at full strength, and diluting them lets a perfumer control exactly how much of an effect comes through in the final blend.

Safety and skin comfort

Some materials, certain essential oils and aroma chemicals among them, can cause skin irritation or sensitisation at high concentrations but are perfectly safe at the tiny percentages actually used in a finished perfume. This is one reason regulatory bodies like IFRA set maximum usage limits for specific ingredients, and reputable perfumers work within them. It’s also why undiluted essential oils are generally not meant to go straight on skin even though the finished perfume containing a trace of that oil is fine.

Control and blending

Dilution also gives a perfumer precision. Something like civet, or a very potent aldehyde, might only ever be used at a fraction of a percent, and working with it pre-diluted makes it possible to measure and blend accurately rather than guessing with a substance too concentrated to dose reliably. It’s a similar principle to why attars and perfume oils are often cut with a carrier oil rather than used neat. For more on how raw materials become finished fragrance, see our perfume ingredients guide and complete guide to perfume.