RogueRose - 6-2-2016 at 13:48
I'm kind of confused as to how some of these companies come up with their scented "essential oils" from all kinds of plants. I also see regular oil
from the plant that seems to be missing the scent although there may be some trace of the scent in the oil but nothing like the "essential oil". Can
someone explain what the differences are in this and how they go about extracting them is it is different?
An example I came across is coffee oil vs coffee essential oil. Price for coffee oil is like $100+ /gal in some places and the essential oil is
$40-80 per oz in some places! Granted I think some of these stores/sites have bizarre prices in hopes of selling just once to make a LOT of $$, but
those prices are somewhat representative of the difference between the two oils.
Another example is orange oil. Some is extracted from the rinds and others from the flowers. The essential (scent oil) is from the flowers and the
rind oil is the less expensive (although scented as well) and can be made into butters as well.
Can anyone help me understand a little better, especially related to the coffee example?
UC235 - 6-2-2016 at 14:55
Essential oil refers to water-immiscible compounds volatile with steam. These are the fragrance compounds from spices, flowers, etc. Any other plant
oil (also known as fixed oils) refers to expressed or extracted nonvolatile oil from the plant in question, which is almost always 95% fatty acid
triglycerides with some ocassional plant sterols or hydrocarbons. The biggest exception is probably Jojoba Oil which is composed of unsaturated wax
esters (fatty alcohol fatty acid ester).
There is no such thing as coffee essential oil and is sloppy product labelling on their part. It's all pressed, hexane or supercritical CO2 extracted
which does not separate the volatile and nonvolatile components. The majority of the product is triglycerides, especially of oleic acid. That being
said, the fragrance components are also extracted and are just left mixed in. You may also see "fragrance oils" on the market which are artificial
scent blends. I honestly don't think you'll ever see actual roasted coffee oil for $100/gallon and strongly suspect that is artificial fragrance.
As far as cost, the natural product is very expensive but very potent. I make lip balms using one such item. A normal lip balm tube is just over 4g of
product. A single ml of coffee oil is sufficient to flavor about a dozen tubes which sell for $3 each. The cost per item is minimal.
Orange "essential" oil is typically actually cold pressed from industry waste orange peels. Unlike the coffee oil almost all of it is volatiles. It's
about 95+% D-limonene. You can purchase this type of oil from sweet orange, bitter orange, blood orange and just about every other citrus if you
looked hard enough.
The issue with using citrus essential oils in personal care products is many are phototoxic due to the presence of furanocoumarins (namely bergapten
and psoralen). Sweet orange notably lacks any appreciable furanocoumarin content, while bergamot, bitter orange, lemon, lime, and grapefruit are quite
bad.
Distilling any of these oils eliminates the furanocoumarin content which is nonvolatile and doesn't contribute to scent. These are less commonly
available and would be at increased cost due to processing. The scent may also be somewhat less true to the source material due to the heating
involved.
While the limonene content of citrus oil is a significant contributor to scent, it is one of the most volatile components and doesn't last in cosmetic
products that sit open to air (such as soaps). As a result, companies sell "folded" citrus oils. 5 fold for example would come about from
fractionating about 80% of the volume out of a stillpot full of cold pressed oil. The distilled product is sold as limonene for scent formulation or
solvent use. The still bottoms contains increased levels of higher-boiling components such as citral that don't fade as quickly in product use.
Bitter orange blossom essential oil is called neroli. It is among the most expensive essential oils due to the vast amount of source material needed
for tiny quantities of finished product. Removing flowers also prevents oranges from forming and so producing it must account for this in costs. The
chemical composition of neroli is quite different from peel oil. They do not smell alike.
"Orange Butter" or "Coffee Butter" is a marketing gimmick by cosmetic suppliers to sell product to amateur cosmetic makers who don't know any better.
It's just the essential oil mixed into (usually) partially hydrogenated soybean oil.
[Edited on 7-2-2016 by UC235]