Because I make things that contain water, like mists and lotions, I use preservatives. As you may have picked up on in my blog posts, I highly encourage you to also use a good broad spectrum preservative. If you balk at the thought of it, please understand that a tiny bit of preservative in your final product is much better than the risk of invisible bacteria or fungi all throughout it. Also, if you’ve ever had the perfect lotion you worked hard on grow mold after just a few days, you’ll quickly become a fan of a good preservative.
There are a lot of broad spectrum preservatives readily available from DIY suppliers. My favorite place to purchase preservatives is Lotion crafters. Here are a few of the preservatives available for home use:
Liquid Germall Plus
Optiphen series (can destabilize emulsions)
Phenonip (contains parabens)
Leucidal (not truly a broad spectrum preservative)
NataPres (not truly a broad spectrum preservative)
The following are sometimes sold in the “preservatives” section but they are not preservatives, rather antioxidants. They will extend the shelf life of your oils and butters in anhydrous products but offer no protection against mold or bacteria in items that contain water.
Grapefruit Seed Extract
Vitamin E oil
Some preservatives are safer than others, and some are more effective than others. That’s a good reason to research them all and figure out which ones will work for you and the products you’re making. The Environmental Working Group’s Skin Deep database is a great place to research the safety of different preservatives. I also encourage you to read everything about the preservative from the supplier to determine if it will work in your products. Effective pH range and solubility are important things to consider.
NeoDefend™, NataPres ™, GeoGard ECT ™, and Leucidal are going to be the safest looking preservatives you’ll research, but unfortunately, from what I can tell, they aren’t the best choices. NeoDefend™ can’t be used with Vitamin C products and the final pH must be below 5. NataPres ™ and Leucidal are not true broad spectrum preservatives and require secondary preservatives to ensure efficacy. For people like you and me, working out of our homes or shops attached to our homes, these preservatives are difficult to use reliably and safely.
I use Liquid Germall Plus for my day to day, routine items like lotions and body sprays, and Phenonip for anhydrous products that are at risk of contamination like sugar scrubs or salt scrubs. Both are effective in very small quantities (around 0.5-1% of the total finished product), and have a broad effective pH range. They are not easily accidentally deactivated. You are unlikely to need to test the pH or adjust it. The usage rates, as mentioned, is low, even at the maximum amount; and I always use the maximum amount despite trying to keep things as clean and sterile as possible while formulating. I used to use Optiphen ND and since I still have a bottle I’m trying to use up I tend to use it in water based concoctions like bug spray or essential oil mists. I used some in a sunburn spray and some in an alcohol free aftershave. It’s been versatile and useful, which is nice, because it was horrible in lotions and broke my emulsions, something that all the preservatives in the Optiphen line are prone to do and is why I don’t recommend them for beginners or for emulsions at all. Liquid Germall Plus is much easier to work with.
How much do I need to use?
Each preservative will have a different recommended usage rates, which you should get from the supplier.
After that, it’s a simple matter of doing a little math. Let’s say your preservative should be used at 1%. If your recipe contains 120g or 4 oz of ingredients, that’s going to require 1.2g or 0.04oz of preservative. That’s not super precise (original recipe plus preservative equals 101%) but when working at home in these small quantities, it’s close enough. Figure out how much your recipe weighs by adding up all the ingredients or weighing the final product, then calculate the preservative and add it in. It’s that simple.
To read more about preservatives, check out the Point of Interest blog. Susan wrote a series of detailed entries about preservatives.