Choosing a preservative is one of the most important things you can do to produce a beautiful and safe homemade product. The first task is to determine if it requires one. If it doesn’t contain water – if it’s an anhydrous product composed entirely of oil soluble ingredients - and won’t be exposed to water, you don’t need a preservative. It’s a good idea to include an anti-oxidant like Vitamin E or rosemary oleo extract to extend the shelf life of your oils and butters, but you don’t need to worry about contaminants like bacteria, mold, or yeast because they need water to grow. Products like whipped butters, lotion bars, lip balms, salves, and other oil only products fall into this category.
If you are making a product that contains water or might be exposed to water, then you definitely need a preservative. Lotions, scrubs, body washes, conditioners, toners, shampoos – all of these need some kind of preservative. Without one, you’ll see contamination in a short period of time, in as little as three days.
When looking for a preservative, ideally you’ll choose a broad spectrum preservative, one that battles all the beasties of contamination. Liquid Germall Plus, Germaben II, Phenonip, Geogard Ultra, Optiphen ND, Optiphen Plus, Suttocide A, liquid Leucidal, and Advanced Aloe Leucidal fall into this category. If you choose a preservative that isn’t broad spectrum, you’ll have to combine it with something else to ensure you get the greatest protection possible. Sodium benzoate, polyaminopropyl biguanide (Cosmocil CG), and Natrapres work well against bacteria, while sorbic acid and Liquipar oil are good fungal, mold, and yeast inhibitors. Check the suggested usage rate for each ingredient, then combine them to create a preservation system for your product.
If you're making natural products, you may wish to consider a preservative with an ECOcert designation, like Leucidal, Advanced Aloe Leucidal, and Natapres. These are all relatively new ingredients, and there are some concerns that they aren’t working as effectively as expected. If you choose to use one of these natural preservatives, use it at the maximum rate, and consider investing in preservation efficacy or challenge testing if you plan to sell.
How do you figure out how to use your chosen preservative? Some are heat sensitive, some are not, so the best suggestion is to ask your supplier for their recommendations. Liquid Germall Plus, Germaben II, Suttocide A, and Advance Aloe Leucidal go into the cool down phase, while Phenonip, Cosmocil CQ, and Geogard Ultra are used in the heated phase.
All preservatives come with a suggested usage range. Liquid Germall Plus is used at 0.1% to 0.5%, Germaben II at up to 1%, Geogard Ultra at up to 2%, and Leucidal 2% to 4%. If you’re using a high percentage of proteins, botanicals, extracts, or hydrosols, consider using the upper range of the suggested usage rates as those ingredients can be hard to preserve.
One preservative does not fit all. For each product, you’ll have to consider a few things before finding one that works best, like the suggested pH ranges, oil quantity, charge, and ingredients. Cosmicil CQ isn’t compatible with anionic surfactants, so using this in a shampoo or body wash isn’t advised. Germaben II and Phenonip may be inactivated by ceteareth-20 or polysorbate 80, which can be found in some emulsifying waxes. Optiphen ND works best for products with a pH of 5 to 6 – which is a very small pH range – and can be inactivated by proteins and cationic (positively charged) ingredients, which means it’s not a good choice for products in which you might use a cationic emulsifier like Incroquat BTMS-50 or Rita BTMS-225, like hair conditioners. Optiphen and Optiphen Plus have the potential to de-stabilize emulsions, and it’s suggested that you add these preservatives in the cool down phase at 45°C to 55°C and continue mixing until cooled to room temperature to prevent curdling. (I don't suggest these for beginners.)
Preserving your product well is about more than the preservatives. Consider the packaging you’re using with your products. Containers that allow less air to enter, like Malibu or tottles or those with foamers, pumps, disc caps, or slit caps will be better protected than jars or bottles with screw off caps. Don’t recycle plastic containers as it’s hard to ensure they are completely clean, and that can lead to contamination of your new batch of lovely product.
Keep your workspace tidy and clean. Sanitize your countertops, scale, and mixing containers before using, and follow the principles of food preparation, like tying back your hair and washing your hands frequently to ensure your products start their lives as contamination free as possible.
Use distilled water in your creations, and source your ingredients from suppliers you can trust.
What do I use in my workshop? My personal favourite is liquid Germall Plus, which works with just about everything I make, including lotions, hair care, and facial products. I’ve had two lotions – both in jars - grow green grossness, and one of those I tortured on purpose to see how well it would stand up to being stirred with a less than clean spoon and sticking my wet fingers into it. Surprisingly, it did well for quite a few months, thanks to the power of effective preservatives!
Your beautiful handmade creations deserve to be safe and stable, and including an effective preservative ensures they will.References:
American Cancer Societyhttp://www.cancer.org/cancer/cancercauses/othercarcinogens/athome/antiperspirants-and-breast-cancer-risk
National Cancer Institutehttp://www.cancer.gov/about-cancer/causes-prevention/risk/myths/antiperspirants-fact-sheet
Royal Society of Chemistryhttp://www.rsc.org/images/parabens_tcm18-219158.pdf
Sense about sciencehttp://www.senseaboutscience.org/pages/parabens-in-cosmetics-an-office-experiment.html
Dr Joe Schwarczhttp://www.montrealgazette.com/health/Schwarcz+Right+Chemistry+Paraben+phobia+unjustified/10133470/story.html
Chemical and Engineering Newshttp://cen.acs.org/articles/92/i23/Close-Scrutiny-Cosmetic-Preservatives-Continues.html
Badger recall informationhttps://www.badgerbalm.com/t-recalls.aspx
Personal care truthhttp://personalcaretruth.com/2010/07/honeysuckle-extract-the-new-paraben-debate/http://personalcaretruth.com/2010/07/honeysuckle-plant-extract/http://personalcaretruth.com/2011/05/a-closer-look-at-grapefruit-seed-extract-gse/