SESH FRAGRANCE ACADEMY | ADVANCED
Does a 15% fragrance loading mean every ingredient is at 15%?
Linalool contains an OH alcohol group. One functional group is insufficient to predict every molecule’s odour or the performance of a mixture.
Open full-size image ↗Calculate concentrate loading by mass and distinguish total fragrance from individual constituent exposure.
Two distinct compositions
A fragrance concentrate is itself a mixture of aromatic and potentially supporting materials. The finished product contains that concentrate within a vehicle that may include solvents and other functional ingredients. '15% w/w concentrate' means 15 grams of concentrate in 100 grams of finished product, not 15% of each aroma chemical. Always distinguish mass percentage from volume percentage.
Mass balance: a worked example
For a hypothetical 200 g product at 12% w/w concentrate loading, the concentrate mass is 200 × 0.12 = 24 g, leaving 176 g total for the other components. This is only a mass-balance calculation, not a skin-safe recipe and not a declaration that all remaining mass is ethanol. The actual vehicle requires its own safety, stability and compatibility design.
Oil droplets dispersed in water: a real emulsion example, not a photograph of a SESH formula or proof of cream efficacy.
Open full-size image ↗Propagate individual ingredient concentrations
Suppose material X constitutes 2% w/w of the concentrate, and concentrate loading is 10% w/w in the finished product. X reaches 0.02 × 0.10 = 0.002, or 0.2% w/w final. Additional contributions from the vehicle or other botanical mixtures must be considered. Concentrate loading alone does not describe the finished exposure of each restricted constituent.
Do not mix w/w and v/v without density
Twenty milliliters need not weigh twenty grams, particularly for alcoholic liquids and fragrance oils. Converting volume to mass requires reliable density at specified conditions. Clearly label % w/w and % v/v; do not combine them as if equal. Mass-balance exercises are simpler with grams, but numeric precision should match measurement capabilities and material specifications.
IFRA limits refer to finished-product exposure
For quantitative IFRA restrictions, limits apply to the finished consumer product in its relevant product category, not just an isolated fragrance concentrate. A material's final concentration depends on all contributing sources and the selected loading. Conformity paperwork does not replace a full safety assessment or applicable national regulations.
Product type changes what must be checked
Eau de Parfum and body mist are product labels, while exposure categories depend on actual intended consumer use and current guidance. Do not assume products share the same limits solely from naming. Establish the use case before verifying applicable restrictions. Vehicle composition also affects solubility, packaging and stability, separate from odor character.
Present auditable loading calculations
A traceable worksheet records finished batch mass, fragrance loading, concentrate mass, vehicle mass, and applicable restricted-material fractions in concentrate and final product. Where supplier composition is confidential, obtain appropriate compliance and use-limit documentation rather than guessing. Mark classroom calculations clearly as educational and not safety-approved manufacturing instructions.
Case study: don't lose the missing 176 g
For a fictional 200 g product at 12% concentrate: 24 g fragrance and 176 g other components. If X makes up 2% of the concentrate, X mass is 0.48 g and final content is 0.24% w/w. Neither the vehicle identity nor the safety of that value can be inferred from arithmetic alone.
Practical case and exercise
Calculate 8%, 12% and 18% w/w loading for hypothetical 250 g batches, then final Y concentration if Y makes up 1.5% of the concentrate. Label every unit and the independent safety review required.
Concept maps and key ideas
Concentrate versus finished product
- Concentrate = fragrance blend
- Vehicle = other ingredients
- Finished mass = combined mass
Mass-balance examples
- 200g × 12% = 24g concentrate
- Other components = 176g
- 2% × 12% = 0.24% final X
Safety calculation checklist
- Specified consumer use category
- Contributions from all sources
- Final-product IFRA limits
- Independent safety assessment
Scientific glossary
- w/w
- Mass fraction: component mass ÷ total mixture mass × 100%.
- Vehicle
- The finished product's carrier system containing concentrate and other constituents.
Further scientific reference
Reference starting points for fragrance terminology and verification: IFRA Fragrance Standards · PubChem
