Essential oils aren’t just for diffusing! DIYs are a fun, creative way to make use of your essential oil collection. But when not formulated properly, you can run the risk of exposing yourself to mold and bacteria (yuck!). Luckily, you can use a preservative to help any water-based stay safe and ready for use.
Preservatives are necessary for water-based products to prevent the growth of mold, bacteria, and fungus. Also, any product that comes in contact with water will need a preservative. A great example of this is sugar scrubs! Since they are used in the bath, they come in contact with water and should be protected.
Common DIYs That Need a Preservative
There are many different kinds of DIYs with essential oils that may need a preservative. Here are some of the most common projects where you’ll want to consider adding a preservative:
- Foaming Hand Soap
- Lotions (made from scratch)
- DIY Spray Cleaners
- Linen Sprays
DIYs That Don’t Need a Preservative
There are, of course, DIYs that won’t need a preservative. Here are some examples:
- Bar Soap: Bar soap does not need a preservative because the pH levels are too high to allow the growth of bacteria
- Essential oils diluted in a carrier oil
- Oil-based facial serums
- Lotion bars
These do not need a preservative since they do not contain water.
But which preservative should I use?
There are a few preservatives that are broad-spectrum, meaning they protect against mold, bacteria, and fungi, and are great for most uses. Other preservatives have limitations and need to be used together with additional preservatives to achieve full protection. Here are some o the most common preservatives, many of which are readily available for purchase.
1. Optiphen Plus
(Phenoxyethanol, Caprylyl Glycol, Sorbic Acid)
Optiphen Plus is a paraben-free preservative that offers broad-spectrum protection for water and oil-based products. It’s effective at pH levels below 6. For this reason, it is not ideal for foaming hand soaps.
- Recommended use level: 0.75-1.5%
- Pros: Paraben-free, formaldehyde-free
- Effective Against: Bacteria, mold, yeast
- Con: Best below pH 6
2. Optiphen ND
(Phenoxyethanol, Benzoic Acid, Dehydroacetic Acid)
Optiphen ND is a water-soluble, paraben, and formaldehyde-free preservative that offers broad-spectrum coverage.
This preservative is great for surfactant-based products, such as shampoo. However, it cannot be used in products with a pH higher than 6 and must be added at temperatures no higher than 176 ºF.
- Recommended use level: 0.2 – 1.2%
-
Pros: Paraben-free, formaldehyde-free,
effective against bacteria, mold, and yeast - Cons: pH: Best below 6
- Temperature: No higher than 176 ºF
3. Euxyl PE 9010
(Phenoxyethanol, Ethylhexylglycerin)
Euxyl PE 9010 is a broad-spectrum, that is great for water-based products that are particularly hard to preserve, such as scrubs that are very low in glycerin, and facial masks that are high in clay.
- Recommended use level: 0.50 – 1.0%
- Pros: Formula pH: No restrictions
- Effective Against: bacteria, mold, and yeast
- Cons: Hard on emulsions so take care when using in lotions and body creams
4. Euxyl K 903
(Benzyl Alcohol, Benzoic Acid, Dehydroacetic Acid, Tocopherol)
Euxyl K 903 is a complete preservative system with a broad, balanced spectrum of efficacy against both Gram-positive and Gram-negative bacteria, yeast and mold.
- Recommended use level: 0.4-1.2%
- Pros: Gentle enough for baby products.
- Effective Against: Bacteria, mold, and yeast
- Cons: pH: Best below 6
5. Leucidal Liquid
(Leuconostoc/Radish Root Ferment Filtrate)
A more natural preservative option that is derived from radish fermented with Leuconostoc kimchii. A peptide Is isolated during the fermentation process and is what gives this preservative it’s anti-microbial effects. Compatible with most ingredients.
- Recommended use level: 2.0-4.0%
- Pros: Accepted by ECOcert as an ingredient in certified organic cosmetic
- Effective Against: Bacteria
- Cons: Not very effective against Yeast and Mold, needs a booster like Potassium sorbate at 0.10%
6. Linen Sprays / Preserving with Alcohol
Linen sprays are a little different. To preserve a water-based spray, use at least 120 proof grain alcohol for 20-30% of the product. Final Ethyl Alcohol concentration needs to be around 15-20% to be effective.
The basic formula would be 75% water, 25% alcohol.
Robert Tisserand has an excellent article, helpful for learning the specifics of using alcohol for aromatic blending.
Resources:
https://theecowell.com/blogs/well/a-guide-to-cosmetic-product-preservatives
https://formulabotanica.com/checklist-natural-preservative-skincare/
http://www.allsortsofsoap.com/preservatives.html
https://www.modernsoapmaking.com/how-to-ph-test-handmade-soap/
