SESH · ADVANCED FRAGRANCE ACADEMY
Compare recovery mechanisms and their effects on extract composition.
Trace vapour from the heated vessel through the condenser to the receiver. This is a simplified laboratory distillation apparatus, not a home perfume recipe.
Steam distillation
Steam contacts plant material, transports some volatile constituents and then condenses. An oil layer may be separated when physical properties allow. Heat exposure and relative volatility can change which molecules are collected. A distillate is not necessarily the odor of a living plant. Record botanical source, process and batch.
Citrus expression
Oil pockets in certain citrus peels can be released by mechanical expression. Resulting extracts can include less volatile constituents than some distillates. Expressed citrus oils differ, and some require attention to potentially phototoxic constituents depending on material and processing. Citrus origin is never an instruction to apply a concentrate to skin.
Solvent extraction and absolutes
Industrial solvent extraction may recover aromatic molecules alongside waxes as a concrete, with further processing yielding an absolute. Solvent residues, impurity limits and extract grade must be controlled. A flower absolute may reproduce some impressions absent from a distillate, but claims of closer fidelity require an actual comparison.
Citrus peel and flesh are different parts of the fruit. Use this as a sensory reference, not a way to infer a formula from a note name.
Supercritical CO₂ extraction
At controlled industrial pressure and temperature, supercritical CO₂ acts as a tunable solvent. It can recover selected compounds under different thermal conditions than distillation. Yield, selectivity and cost still depend on feedstock and process. Pressurized extraction is industrial equipment, not a home experiment.
Choose extraction to serve a brief
Expression may suit certain citrus-peel materials; a solvent-derived absolute may recover aspects of delicate flowers; distillation can serve many herbs and woody plants. No route wins universally. Evaluate odor profile, recovered chemistry, safety specifications, stability and economics against the formulation brief.
Case study: one flower, different products
Compare a steam-distilled rose oil with rose absolute. Their processes and recovered fractions differ; neither deserves a universal quality ranking. Examine target use, quality documents, price and restrictions before selecting.
Practical desk-based exercise
Create a paper decision tree for bergamot peel, jasmine petals, mint leaves and aromatic wood. Select a plausible extraction route and one condition that might change it.
Three diagrams summarizing the lesson
Steam-distillation sequence
- Steam contacts plant
- Transport selected volatiles
- Condense and possibly separate
Four extraction routes
- Steam: distillation
- Mechanical: expression
- Solvent: absolute
- CO₂: industrial pressure
Extract quality record
- Plant and harvested part
- Extraction process
- Batch and impurities
- Restrictions and odor performance
Scientific terms
- Absolute
- Fragrant extract often refined from solvent-extracted plant material.
- Concrete
- Primary solvent extract that may contain waxy constituents.
