In previous posts, I think I’ve addressed the fact that natural oils eventually go rancid. It happens to all of them – probably everyone has had the experience of opening a bottle of olive oil and making a face at the smell.
Natural oil products go “bad” because of oxidation, which occurs when light and air hit the oil. This is why Quadrivium recommends keeping your oils in dark glass bottles and storing them in a dark, cool place. Vitamin E, which is a powerful antioxidant, is used in all of our oils to slow down the process. Nothing will stop an all-natural oil from eventually getting rancid, but using an anti-oxidant additive will make the oil last much longer.
The trick is to find out which kind of Vitamin E oil you have before you add it to an oil. There are two kinds of Vitamin E oil available, one natural and one synthetic. The synthetic oil (dl-tocopherol) has no anti-oxidant properties. Check the label before you buy Vitamin E oil to ensure that it says d-tocopherol, as this means it’s the natural form of the oil and has the anti-oxidant qualities needed.
It only takes a few drops of natural Vitamin E for the antioxidant qualities to work – usually the final product is about 0.04- 0.5% Vitamin E.
Another option that some oilmakers use is benzoin, though Quadrivium does not use benzoin for some reasons that I’ll outline below. Benzoin (styrax benzoin) is a resin, which means it’s sticky and thick. It can’t be added to an oil in it’s natural form. There’s no real essential oil of benzoin, though there’s often products that claim to be essential oil of benzoin. Remember that there are no real rules in place in this regard, and that companies can claim that liquid benzoin is an essential oil when it’s not. In order for the benzoin to be liquid, it has to go through a chemical process often referred to as “solvent extraction.” This means the resin has been chemically processed, and will contain solvents to make it pourable and liquid. Odds are the people using the liquid benzoin have no idea what solvents or chemicals are in their liquid benzoin, which leads to the possibility of carcinogens, allergens, and other issues. In fact, benzoin itself can be an allergen, and there have been cases of people developing a sensitivity to benzoin after using so many products that have used it to prolong shelf life.
This is why Quadrivium does not use liquid benzoin as an anti-oxidant.
Benzoin resin can also be dried and made into a powder, which can be added to an oil, but that presents another set of problems. There is no way of knowing what is in the powder. The label may say it’s 100% benzoin resin, but unless the user has made the powder themselves, there’s no way of knowing which variety of benzoin is being used (there are several), if the powder is pure resin, if there are added chemicals, or how the powder was processed.
Since Quadrivium isn’t a chemical processing company, and we don’t have the means to test powders for purity, we’re not taking the risk with benzoin powder, either.
Grapefruit Seed Extract is another antioxidant that’s often mentioned when talking about natural preservatives, and it is indeed an antioxidant. However, it’s extracted with synthetic compounds, including methylparaben. It’s also something of a newcomer to the “natural preservative” family and while some people have found it effective, it doesn’t have the track records that benzoin and Vitamin E do.
Rosemary (Rosmarinus officinalis) extract, also known as Rosemary Oleoresin Extract, is another powerful anti-oxidant that can be used in oils, though it’s much more common in soapmaking. Per the Camden-Grey essential oil site, which sells this product, an oleoresin is an extraction of a natural food or flavoring raw material using selected solvents to remove the vital components; the oleoresin will contain the essential oil and other important non-volatile components which enhance the flavor, act as fixative or contain other desirable properties. ROE is very strong and some people find it irritating to the skin; it’s also a very thick liquid. Most people disperse it in vegetable oil before adding it to their product. As with Vitamin E oil, it doesn’t take much ROE to work as an anti-oxidant – .1% to 1% in a finished product. ROE has a distinct herbal odor, but so little of it is used in the product that it’s not particularly noticeable.
While this is an excellent product, Quadrivium Supplies believes that every plant ingredient in an oil should have a meaning – and since ROE is extracted from rosemary, it retains the magical properties of rosemary, which aren’t appropriate for many of our oils.
If you want to keep your oils from going rancid, you have many options. We use all natural low d-alpha mixed tocopherols, also known as T-50 Vitamin E.