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I’m an active member in a number of Facebook groups where DIY’ing is the happening thing to do. Along the way, I’ve been able to observe what sort of frequently asked questions are. As a result, I’ve have had the opportunity to teach others a little basic information about product safety and efficacy when and where needed. Many DIY enthusiasts are discovering that making products for body, bath and home goes beyond what the mommy blog or beauty blogger with DIY “recipes” would like them to believe. As people learn that it’s not as cut and dried or as easy as the bloggers and fellow DIY enthusiasts make it sound, they are asking questions. Some of which are fairly simple and straightforward while some are more complicated and beyond what can be taught on social media or even a long blog post. 

Instead of spending hours trying to answer all the questions and tags I get on social media, I decided to start answering some of the frequently asked questions I see here on my blog.  Today, I’m going to share a few of the FAQ and facts about DIY foaming soaps, which seems to be a hot DIY topic and project. Other water-based products are closely related so you may see mention of those in this article as well. So let’s get started with the first Ask The Formulator article, shall we? 

Ask The Formulator-FAQ & Facts

QUESTION: If I add water to my liquid soap to use it in a foamer dispenser, do I need a preservative?

ANSWER:  YES! Although soap is generally self preserving due to it’s high pH, anytime you add water, witch hazel, aloe vera gel or juice, vinegar, hydrosols/hydrolats or other similar additives to “thin down” the liquid soap so it will work in the foamer pump, you are increasing the water that’s available and changing the pH of the mix. Thus providing a breeding ground for microorganisms to thrive in. You may not see them or smell them, but they are there, lurking, partying with their friends, reproducing and attaching to your skin, sink, drying towels, etc. It’s sorta like an unsupervised and out of control rave party……for yuckies. 

QUESTION:  But I add essential oils to my diluted/foaming liquid soap. Doesn’t that kill any bacteria, mold or fungi and preserve it?

ANSWER:  NO! While many essential oils do have anti-microbial properties, the dilution rate you would have to use for the essential oils to provide even a little preservative activity would be well above what is considered safe for dermal contact. In addition, essential oils will not usually offer broad spectrum protection for the hundreds to thousands of different bacterium, mold and fungi that can set up house in your product.

QUESTION:  But it’s soap! Doesn’t soap wash away bacteria and filth? 

ANSWER:  Yes, soap does wash away bacteria and filth. But on surfaces, skin, from fabrics, etc. We’re talking about bacteria and other microbes IN the soap itself and the fact that you are altering a finished product that has been formulated to be safe for consumer use, making it something different than it started out as. When you alter a product by adding things to it, you compromise the formula and the safety of the product, be it a liquid soap, lotion, cream, a gelled product, mascara, liquid foundation, or other. 

QUESTION: I’ve been adding water to my liquid soap for years and never had a problem with it. Now you’re telling me it’s likely unsafe and growing nasty little yuckies like bacteria or mold? 

ANSWER:  Yes, that’s what I’m telling you. You say you’ve never had a problem with it. How do you know? Have you sent it to a qualified lab to have it tested for microorganisms and what type are present….several times…over the course of several months…..up to 3 years out? Truth is, microorganisms are so incredibly tiny that it takes hundreds of thousands into the millions colonizing before you will see one speck about the size of a single coffee ground or smell anything funky. I could take a half a teaspoon of water, put 100,000 bacteria cells into it and you would see nothing but clear water and smell absolutely nothing off-putting. 100,000 microbial cells is enough to cause a skin issue, a respiratory issue or infections. So going by visual appearance or aroma is unreliable. Even going by the feel of it is not a reliable standard of efficacy. Micro-organisms will begin to grow, multiply and colonize within 24 – 48 hours in most cases. If there’s water components in the mix, and other conditions in the mix such as pH, food source, temps, etc. are within a wide microbe’s compatibility range, there will be growth because water is life. It’s prime breeding ground for the little buggers. Guess what? Most of those DIY things you love to make, like foaming soap, are well within the ranges we see growth of bacterial, mold, yeast and fungi in. Even under the most sterile of conditions, which isn’t likely in a typical home or workspace environment, from the very start, there’s likely already microorganisms in the product from the containers, ingredients, tools and utensils, the air and you yourself. You see, microorganisms are everywhere, in and on everything, with millions being on our skin and hair alone, not to mention our clothing, the air, surfaces…..everywhere. Some are harmless and even beneficial but some are not. Without a chemical substance specifically designed to eradicate and inhibit them, they will grow….and grow….and grow. 

QUESTION:  But aren’t preservatives toxic? They’re chemicals and chemicals are toxic or harmful. 

ANSWER:  Yes, they are chemicals, just like the fixed oils and lye your soap was made with, the water you want to put in your liquid soap and the essential oils you want to add for fragrance. Everything is chemical or composed of chemicals so to say chemicals in general are toxic is an uninformed blanket statement. All chemicals CAN be toxic at or above certain levels or from specific exposure method, be they natural or synthetic chemicals. But chemicals are not toxic or harmful regardless. Not all chemicals that can cause toxicity or may cause harm do so no matter what. That again, is an uninformed statement. Toxicity is dose/exposure dependent. Even you beloved essential oils can cause toxicity in the right dosage. Quite literally, the poison, which is the definition of “toxin”, is in the dose. Used properly and with knowledge, the broad spectrum preservatives available for cosmetics and home care products are safe with no danger of toxic buildup or effects. The pseudo-science and mass spread of fearmongering surrounding them are really unfounded and not scientifically sound. It’s just chemophobia and chemical illiteracy doing what it does. On a parallel vein, contrary to what many say, very few substances used on the skin can pass the skin barrier to be absorbed into the bloodstream or internal tissue. We’re talking less that 5-10%. The molecular size and structures of preservatives are generally just too large to get through the little built-in force field the good Lord gave us as protection. But then again, He’s really smart that way.

QUESTION: What preservative should I use for my diluted or foaming liquid soap? 

ANSWER:  While we (professional formulators) would love to be able to say, “Use this preservative for all your water-based products and emulsions.” or “Use this at this amount in this product to insure efficacy.”, we just can’t. So many factors must be considered for what preservative ingredients and system is right for each different finished product. Among them:  What are the ingredients in the product? At what rate was each used? What’s the pH of the finished product? Does that pH change over time? Is it an oil in water or a water in oil emulsion? Is it mostly water or all water like in a spray or oil-free gel? How much water availability is present? What temps will likely be involved in the production and subsequent storage of said product? Does it contain an ingredient which will render the preservative system ineffective? What is the ionic activity? Does it contain any cationic ingredients? What about anionic ingredients? Any nonionic ingredients? Or amphoteric ingredients? Are any of the ingredients deionized? Is the whole of the formula positive or negative charged? Does it contain botanicals or food stuffs? Or maybe it contains clay? Does it contain any humectants? What is the water-holding capacity of the humectants used?  Does the chosen packaging effect the stability and efficacy? And the list goes on and on. What works very well for one product may not work as well or at all for another. There’s not a one size fits all and you don’t know if your choice works for that particular formula unless you have it tested for efficacy and stability by a microbiology lab that performs those specific tests. Not an inexpensive thing, I might add. Keep in mind, we are dealing with chemistry and microbiology here. Stable, safe products don’t just happen. They are very meticulous and intentional.   

There are some really good, reliable, and safe broad-spectrum preservatives, which are a combination of gram-positive and gram-negative bacterial inhibitors partnered with mold/fungi and yeast inhibitors, as well as any preservative assists out there that give good results within reason with well-planned formulating using the right protocols and hurdles. Of course, everything has limits and defined capabilities. Preservative systems for cosmetics and home care products are no exception. Yes, I said systems because we’re dealing with chemistry and combined ingredients here, not just one ingredient. Every ingredient in the mix impacts the safety, stability and efficacy of the finished product. All the questions I mentioned above and more need to be addressed and evaluated. Even then, without efficacy, stability and challenge testing, no one can say for sure any preservative and preservative assists are adequate for the formula they’re used in. Even with professional formulators and chemists, the best we can do is make an educated guess based on what we do know and our experience, work within specific parameters and guidelines for each product, and plan well from start to finish.  Then we must have our product tested for efficacy and stability to find out if our educated intention and formulating skill worked in that particular product. 

As I said above, there are some very good broad-spectrum preservative products available. There are also individual microbial inhibiting ingredients on the market with good track records and proven efficacy within their specs of use for one to customize a preservative system for any given product. But no broad-spectrum preservative product nor individual or combination of microbial inhibiting ingredients sold today will be sufficiently suitable for all product formulations and all the variables involved. I cannot say any of these will work with a particular DIY “recipe” or that they will work effectively on anything or everything you try to make. The fact is every formula will require something different based on the ingredients in it and proportions as well as packaging being used, expected use and storage parameters plus other factors. I cannot give recommendations in a generalized manner nor make any guarantees. Neither can anyone else with any product formulating and cosmetic chemistry education and experience. If someone says they can or tells you “just use X” or “I use Y”, they are not educated or experienced here. So keep that in mind in the future. If you don’t know what any and all of the above mentioned means or how to evaluate and access them, then you can’t either. Nor can you formulate a foaming hand soap or any other product with water components that will be stable and safe with any assurance.  Sorry, I don’t believe it giving fluff or beating around the bush. 

My advice, which I am well aware may not go over well, is this. Forget the DIY foaming soap. You are not saving money or doing what’s best for you or your family if you’re concocting and using a petri dish of nasties and yuck in a bottle.  I’m not a fan of foaming soaps and foamer pumps at all. You are getting about 75-98% water with a tiny bit of soap or cleanser. Did you know “foam” does not clean very well? No, it doesn’t. Soap cleans. Foam or lather is the result of soap or surfactant cleansers acting with water, friction and aeration. Foam, bubbles and lather are mostly air with a little bit of soapy slip and a lot of water. Think on that for a second. Could it be this is one of the reasons viral and bacterial outbreaks and spreading has steadily been on the rise in the last 10 or so years? I personally think so. Instead, just use a bar soap or liquid soap, wash, shampoo or dish liquid exactly as sold and purchased. It’s already a diluted product at the maximum water introduction rate with appropriate formulation. Or should be. Some I’ve seen lately are a nightmare, let me tell you. Anyways….Wet the hands or whatever skin area you’re cleaning. Use just a little soap/cleanser. Seriously, just a little is needed…as little as one-quarter to one-half a pump squirt is plenty for hand washing. More for body or hair, of course.  Rub and create friction for the time it takes to sing the Happy Birthday song or other favorite song stanza. Don’t forget under the nails, around the nail beds and cuticles, in between fingers and the wrists. Use a nail brush if needed to get into the grooves. This is proven to be a very effective washing routine to remove dirt, grime and germs. A good rinse and thorough drying finishes the task. That’s it. It will also save you money because you aren’t paying for or washing in bubbly water with barely any cleanser that’s not enough cleaning action to break loose the grabby things and doesn’t wash away much at all. Seriously, it’s an illusion of “clean” which we all associate with getting rid of nasty germs along with dirt. Remember, illusions are not as they seem to the eye and mind.

So there you have it. My professional and personal opinion. Take it or leave it. I do hope you take it though. I could benefit you far more than you think.


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