There's nothing like the clean, refreshing scent of citrus oils to awaken the senses. But there is a great deal to learn before buying any essential oils - especially citrus oils.
Quality is always important, but when it comes to citrus, it's absolutely crucial. You want to be sure that the citrus oils you use are organic, unadulterated, and cold-pressed (rather than steam distilled). Here's why.
A growing number of consumers are sensitive to the harmful effects of pesticides and herbicides. With citrus oils, organic is a particularly important quality factor because the rinds of citrus fruits absorb the chemicals when a crop is sprayed, and citrus oils are extracted directly from these rinds.
Citrus oils share a similar scent -- they all contain the terpene hydrocarbon limonene. Subtle mixes of other minor constituents -- unique to each citrus fruit -- produce variations in aroma that allow us to distinguish between them. But that's the only variation you should be able to detect.
Poor quality essential oils are sometimes adulterated with other synthetic oils, producing a tainted scent. If you place a drop or two of an adulterated essential oil on a piece of blotter paper, it will leave an off-smelling dryout note when it evaporates. Pure, unadulterated oils will smell fresh -- much like the fruit itself -- and leave little or no dryout note.
Most essential oils are obtained by steam distillation . But the heat of this process breaks down the acids in citrus fruits and diminishes the citral content of the fresh oil. As a result, citrus oils that are steam distilled often have a sharp, harsh, bittersweet aroma.
"Cold pressed" oils, on the othe hand, are separated from the rind of the fruit (which is not actually cold, but room temperature) by grinding or rasping and then pressing without heat. It's a far less efficient method - yielding only about 1.5 pounds instead of about 25 pounds of oil for every tone of fresh fruit - but the result is a light, subtle, fresh aroma reminiscent of the fresh peel.
Because steam distillation substantially changes the chemical constituent profiles of the oils, cold-pressed citrus oils are preferred by aromatherapists, who rely on them for a range of effects.
The common essential oils considered phototoxic include: bergamot, lime, bitter orange, lemon, rue, angelica root, petitgrain, rue and grapefruit. Some authorities also include lemongrass, cumin, fennel, anise, and verbena absolute on the list.
Consider any cold pressed citrus oil a potential photosensitizer.
Steam distilled citrus oils, on the other hand, do not carry this risk. St. John's Wort CO2 and infused oil are also photosensitizers.
Bergamot (Citrus bergamia) is know to be one of the most photo toxic essential oils and for this reason should be used with care in sunlight, hot climates and with other ultraviolelt light. In concentrations above 1% it can irritate the skin. Also even though it is sometimes added to commercial suntan agents to stimulate melanin production, it must never be used in home mixture for tanning purpose.
Photosensitivity is caused by the presence of furocoumarins, most notably Bergapten, in this particular essential oil. Apart from this factor, Bergamot is considered to be a relatively non-toxic and non-irritant essential oil.
Bergamot oil has a lovely green light citrus/floral note, fruity and warm, much used by
perfumers as a top note. There are two types of Bergamot available: Regular Bergamot
Essential Oil and BergamotFCF (Furo-Coumarin Free) .
FCF at the end of Bergamot indicates that the furocoumarins (namely bergaptene) have been removed by steam distillation. Bergaptene free bergamot (FCF) reduces the susceptibility to photosensitizing and is the preferred bergamot for safe use in massage blends and in perfumes.
Lime essential oil (Citrus aurantifolia) has many of the same uses as Lemon Oil, but with a lighter, sweeter buoyant scent. Lime oil can be extracted by expression or by distillation - the peel of the unripe skin by cold expression or the peel and /or the whole ripe fruit by steam distillation. Lime oil obtained by steam distillation of the fruit rinds does not have a phototoxic effect on the skin so is wonderful for skin care.
According to Tisserand and Balacs in Essential Oil Safety, the expressed oils of mandarin, sweet orange, tangelo and tangerine are not phototoxic. This is due to the quenching effects of other compounds, especially sesquiterpenes that make the unruly furanocoumarins behave. Myrrh is a perfect example. It contains at least ten types of furanoid compound (20-27%)-more than any other oil, yet it is not phototoxic. In ancient times, they actually used myrrh oil on the skin daily without sunburn reactions.
The information on this post is just some of the information I have learned about citrus oils. It is your responsibility to take the necessary care when purchasing and using citrus oils.