Welcome to our Perfume Primer, a reference tool for the technical terminology used in bespoke perfumery. This glossary lists and defines the specialist terms used in the process of creating a custom fragrance. The aim of this documentary resource is to clarify the fundamental concepts, processes and components used by professionals in the sector. The definitions set out in a factual and precise manner the technical elements needed to understand the professional vocabulary, making it easier to approach the specialised aspects of designing a made-to-measure fragrance.
Absolute: a mixture of mainly fragrant molecules obtained mainly by the maceration or enfleurage process.
Eau de Cologne: VOC concentration of 4 to 6%. Very light, it is composed mainly of citrus and aromatic notes. Eau de Cologne originated in Germany in 1792.
Eau de parfum: 8-20% concentration, more in-depth work on the heart notes, a composition between two different eaux de parfum.
Eau de toilette: 3-10% concentration, more in-depth work on the top notes, a fresher, airier, lighter composition.
Enfleurage: an age-old extraction technique used in perfumery to capture the volatile essences of flowers, particularly those that cannot be extracted using other methods. This is the case for jasmine. This technique relies on the ability of fats to naturally absorb odours. At the end of this process, we obtain an absolute.
There are two main types of enfleurage:
- Cold enfleurage: freshly picked flowers are placed on frames covered with a thin layer of animal or vegetable fat. The flowers are regularly replaced until the fat is saturated with fragrance, an extremely long process.
- Enfleurage à chaud (or maceration): a traditional extraction technique used to obtain soluble compounds from a solid material. This method involves immersing the raw material in a solvent at room temperature for an extended period, ranging from a few hours to several weeks. This process can be repeated with different solvents.
During enfleurage, other molecules, such as coloured molecules, are carried away. This is why absolutes are generally darker than essential oils, but also because heavier fragrance molecules are not carried away during hydrodistillation. The result is a more intense fragrance with stronger base notes. You can compare rose extracts obtained from essential oils and absolutes.
Essential oils: a mixture of mainly fragrant molecules obtained mainly by the hydrodistillation process.
Extraction using supercritical CO₂: a particularly environmentally-friendly extraction technique distinguished by its minimal environmental impact. This method operates in a closed circuit, avoiding the emission of greenhouse gases or toxic substances. Although very environmentally friendly, it involves high costs. CO₂ is favoured for its ability to reach a supercritical state, an essential quality for treating the delicate raw materials used in perfumery, such as petals, which would be damaged by the high temperatures of hydrodistillation. Being non-toxic and chemically inert, CO₂ is an ideal solvent for sensitive materials.
This extraction process is based on the use of carbon dioxide in a supercritical state as an extractant. CO₂ reaches this particular state – intermediate between gas and liquid – when exposed to specific conditions exceeding its critical points (31°C and 74 bar). In this state, it combines the advantages of a gas (low viscosity) and a liquid (high dissolving capacity). To extract volatile organic compounds from a matrix, CO₂ is maintained in a supercritical state. Once the extraction is complete, the CO₂ is transformed into a gas, allowing the pure product to be recovered, without solvent residues. The CO₂ is then recycled for subsequent extractions, ensuring an environmentally friendly process.
Filtration: the perfume is filtered to remove solidified impurities, resulting in a clear, translucent juice.
Fragrance: concentration of 15 to 30%, more work on the base notes, heavier composition, less airy, more presence.
Gas Chromatography – GC: gas chromatography is an analytical technique used to separate, identify and quantify the components of a mixture, mainly those that are volatile. This method is based on the interaction between a gaseous mobile phase and a solid or liquid stationary phase fixed inside a capillary column. In the GC process, the sample is vaporised and then injected into the chromatographic column. The components of the mixture interact differently with the stationary phase depending on their boiling point and chemical affinity, allowing them to be separated.
One or more detectors linked to a computer are used to identify and quantify each molecule, providing a detailed profile of the components present in the mixture. However, for VOCs, an olfactory analysis module can be added. The separated molecules are then sent into a pipe where an olfaction specialist can smell them and determine their olfactory properties (odour, intensity, trigeminal property).
GC is widely used in perfumery for the analysis of volatile compounds, quality control and the creation of new fragrances.
Glazing: a technique which involves cooling the fragrance mixture to a temperature below 5°C, or even around 0°C, in order to precipitate and solidify impurities, such as waxes and resins, which could cloud the appearance of the fragrance. This step is essential to guarantee the visual and olfactory quality of the final fragrance.
Head space: a technique used in perfumery and analytical chemistry to capture and analyse the odorous molecules present in the air surrounding an object, flower or environment. This method makes it possible to reconstitute natural odours that cannot be extracted using traditional methods, such as essential oils.
Hydrodistillation or EO: a process used for many plants (e.g. roses). The process involves heating a mixture of water and the raw material to be extracted until it boils. The water vapour formed then carries with it the volatile compounds and the future essential oil contained in the raw material. This vapour is then cooled in a cooler, causing the vapour to condense into a liquid. This liquid contains both the water and the essential oil, which tend to separate naturally due to their lack of miscibility. The essential oils, which are less dense than water, float to the surface, while the water, called hydrolat, remains below.
EO is a steam extraction process. Water vapour carries lighter chemical molecules with it. These molecules are more volatile, giving a more subtle scent than when extracted by enfleurage. You can compare rose extracts obtained from essential oils and absolutes.
The object is placed under a glass bell jar in which a neutral gas circulates. The odorous molecules then diffuse into the air and are captured by a very fine rod, such as activated charcoal or polymers, which act as an absorbent. They are then analysed by GC, enabling the perfumer to recreate a fragrance similar to the original scent.
Isolated molecule: this is a single molecule, not a mixture of several molecules as in the case of essential oils or absolutes. It is obtained by extraction from a plant, like natural vanillin. Or by synthesis in a laboratory. They may also not exist in their natural state and be created by man, such as ethyl maltol or certain musks.
Maceration of a fragrance: once a fragrance has been formulated, the ingredients must be given time to interact with each other and allow the fragrance to form. It takes about two months for the interactions to take place. This process is called ‘maceration’.
Olfactory pyramid: a key concept in perfumery which describes the structure and evolution of a fragrance through three distinct levels: top notes, middle notes and base notes. These levels correspond to the volatility and persistence of the different scents.
The olfactory pyramid allows the perfumer to structure a fragrance so that it evolves harmoniously over time. It guides the balance between initial freshness, lasting character and persistent depth.
Perfume organ: professional cabinet in which perfumers store and organise the bottles containing the raw materials needed to create perfumes. This piece of furniture, often in a semi-circle, allows the perfumer to arrange his plant, animal or synthetic essences in a practical way for the composition of perfumes.
The use of the perfume organ is similar to the vocabulary of music: “notes” and “chords” are combined to create an olfactory harmony. The top, middle and base notes are the key elements of this olfactory pyramid.
Sillage: the olfactory trace that a fragrance leaves behind.
Top, middle and bottom scores: each VOC can be classified in one of three categories according to its volatility: top score for the most volatile, middle score for medium volatility VOCs and bottom score for the least volatile.
- Top notes: these are the first scents perceived after applying the fragrance. Light, fresh and volatile, they evaporate quickly (approximately 15 to 30 minutes). Examples: citrus fruits, aromatic herbs, etc.
- Heart notes: these are the very essence of the fragrance. These notes appear after a few minutes and last for several hours (4 to 6 hours). Examples: flowers, fruit…
- Base notes: these are the most persistent and deepest scents, forming the basis of the fragrance. They evaporate slowly and can last several days. Examples: spices, wood.
Volatile Organic Compound – VOC: a chemical substance characterised by its ability to evaporate easily at room temperature. Their main characteristics are as follows:
- They are compounds containing carbon (hence the term ‘organic’),
- They have a high vapour pressure at room temperature,
- They change easily from a liquid to a gas,
- Their boiling point is generally low.