Essential Oil Notes in Soapmaking
This comes up a lot in soapmaking groups, and it’s often misunderstood. Top, middle, and base notes are properties of the essential oil itself — not the percentage you use in a recipe. Each essential oil has a natural evaporation rate based on its chemistry: Top notes Light, fast-evaporating oils. They smell bright at first but fade fastest in soap. (e.g. citrus, eucalyptus) Middle notes Moderate evaporation. These usually form the main body of a soap scent and hold reasonably well. (e.g. lavender, rosemary, geranium) Base notes Heavy, slow-evaporating oils. These help anchor blends and improve scent longevity in soap. (e.g. patchouli, vetiver, benzoin) Common misconception Changing the ratio does not change the note category. Example: Lavender = middle note Rosemary = middle note A 60/40 or 50/50 blend doesn’t turn one into a top or base note — they are still both middle notes. The ratio only affects which scent is more noticeable, not how the oil behaves chemically. What actually matters in soap Top notes fade the fastest during cure Middle notes usually survive cure better Base notes help anchor the blend and extend scent life Balanced blends are more stable than single-note formulas Understanding this makes scent blending in soap simpler, more predictable, and less frustrating. Safety note (because it matters): Always calculate usage rates for soap and IFRA categories before formulating — understanding scent structure never replaces safety checks.