Are fragrance oils the same as the aroma chemicals

you use?

FRAGRANCE OILS

In perfumery the term Fragrance Oils is used to mean

a Perfume Compound. They are complex mixtures of different

types of aromatic materials, mixed together by the creative

perfumer in response to a brief received from a finished

goods manufacturer that requires a concentrated perfume

to add to his/her product.

The professional compounder uses several different types

of material to create a perfume compound – aroma chemicals

(synthetically produced aromatic molecules – usually a

single molecule), essential oils (natural extracts obtained

by steam distillation or expression), absolutes (natural

extracts obtained by solvent extraction), specialties

(produced by perfume houses and unique to that house.

They are usually simple compounds or aroma chemicals with

a relatively high level of impurities that make

them distinctive), bases (perfume compounds produced by

a perfume house), and captive chemicals (patented aroma

chemicals that have not yet been released to the market

but kept in house for use a company’s own perfume compounds).

Fragrance oils (perfume compounds) are highly concentrated

and are invariably diluted before application to the skin.

The diluents can be oils (diethyl phthalate, dipropylene

glycol, iso-propyl myristate etc), or ethanol, or the

product base itself. Since it is uneconomical to ship

solvent, dilution normally takes place close to the

finished product line.

ESSENTIAL OILS & ABSOLUTES

Essential oils are natural oils obtained from aromatic

plant material. They are usually produced by steam

distillation (boiling it out) where steam is driven

into the plant bursting the cells that contain essential

oil. The oil turns into a vapour and this, plus a great

deal of steam is condensed back into liquid form and

collected in a receiver. The oil will separate from the

water and float on the top or sink to the bottom,

depending on the oil. Since essential oils are created

from vapours, and the nose can only detect vapours,

all of the essential oil has the potential to be smelled.

The water below an essential oil will contain those parts

of the essential oil that are soluble in water. These

can be critical components (phenyl ethyl alcohol in rose)

and may require the producer to compensate for the loss

by adding the materials back into the oil or by adopting

cohobation (recycling of the water). Examples of

distillation waters are rose water (beneath otto rose),

orange flower water (beneath neroli) and lavender water

(beneath lavender oil). Some essential oils are obtained

by expression e.g. from the peel of citrus fruits

(squeezing it out).

Because distillation involves a lot of heat, it can only

be used on plants that have a relatively robust constitution.

Delicate plants like Jasmin, Narcissus, Mimosa etc., are

destroyed by hot processes and require a cold process like

solvent extraction (dissolving it out). The choice of solvent

is critical. Ethanol is a poor choice because although it

dissolves the oil, it is also 100% miscible with water,

and since plant material contains a lot of water, this

would be extracted too and is a problem to remove. For

this reason hydrocarbon solvents are often used but they

too have disadvantages. They bring with them the waxes

from the plant; they are toxic and have to be completely

removed before use; and they dissolve coloured materials

too like chlorophyll.

When the solvent is removed, this leaves a concrete - a

solid waxy lump. This is then gently warmed in ethanol

and the waxes are filtered off yielding an alcoholic

extract solution. The ethanol is vacuum distilled off,

leaving an absolute (if you distil in a vacuum, the

temperature is kept much lower). Absolutes tend to be

more expensive than essential oils due to the fact that

solvent extraction is a multi-stage process.

Today, many different solvents are used with the aim

of keeping the temperature as low as possible in order

not to lose the highly volatile “head space” of the natural

material. Solvents include butane and carbon dioxide.

There are many essential oils and absolutes that are

harmful to use in 100% concentration.

NATURAL FRAGRANCE OILS

The name suggests that natural fragrance oils are perfume

compounds that have been created using 100% natural materials.

However, since “natural fragrance oils” is not a recognised

phrase, it is best to check with the supplier as to the

exact meaning.

Thanks to Frank and John