If you make homemade hair gels (I won’t discuss other products right now because ionic-charged ingredients in conditioners or shampoos makes preserving more complicated), and you do not store them in the refrigerator – or if you usually do, but are going away from home, then you need to think about preservatives. This refers to flaxseed based gels, vegetable gum based gels (guar gum, xanthan gum), aloe based gels, or any other vegetable-based gel (psyllium, okra…).
©Science-y Hair Blog 2013
How Can A Product Go Bad?
Rancidity can happen to oils (aka oxidation) if you use them.©Science-y Hair Blog 2013
Bacteria or fungi can grow, using the sugar and nutrient-rich gel for food, also excreting their metabolic wastes into the gel causing cloudiness, fermentation, changes in thickness and texture and odor.
These are the biggies, not only because they ruin your gel, but because the bacteria (or fungi) growing in your un-preserved, un-refrigerated gel could be pathogenic. Let me get up on my soapbox for a moment. We need not fear bacteria everywhere. Every bit of our bodies is permeated with bacteria and other critters and without them, we would be weak, sick, malnourished and completely different than we know ourselves to be. Having said that, bacteria on your skin, in your guts are not usually making you sick. But if you get a cut, then there’s an opportunity for an infection. If bacteria end up where they should not be, or if they have a chance to colonize a medium and grow like mad (or even form self-protecting biofilms like plaque on your teeth) – then you’ve also got a problem. So if your hair gel turns into growth media for bacteria and fungi and it gets on your hands and then in your eyes, on a tiny cut, in your mouth etc., it’s a problem. Especially for gels based on food-quality items. I found bacteria from the Staph/Strep families, and others which would be food-born pathogens in unpreserved, unrefrigerated, homemade hair gel.©Science-y Hair Blog 2013
If you want to preserve your flax-based or gum-based gels, there are some safe, easy ways to do this. I have tested some preservatives, and my data have been added to by some other people with preservatives I have not yet tested. I began with 2 bases, one was flaxseed gel with agave nectar and hydroxyethylcellulose, the other had olive oil added as well. For each gel, one sample was refrigerated and one was left at room temperature. I did a un-preserved control too. I used a Gram-stain test to detect bacteria in the gels as they were. This is a different method than used by cosmetics companies - but it gives us a rough idea of how our preservatives are working.©Science-y Hair Blog 2013
Preparation Notes: Even if you’re refrigerating your gels, it’s best to use distilled water to prepare them (no chlorine or minerals) and to wipe down all your utensils and nearby surfaces with rubbing alcohol. Remember, this isn’t just "cooking," you’re planning to keep using this for longer than a week – you need to be careful! Put your gel in a bottle with a lid. If it’s in a cup where you’ll be sticking your fingers into it, you dramatically increase the potential for contamination. And spilling (trust me about the spilling bit).©Science-y Hair Blog 2013
Why are preservatives given as percentages? That's the best way to measure. If you need 0.5% (half of one percent) preservative, that is 0.5 grams per 100 grams. Or 1.25 grams per cup (250 grams). 1.25 grams is one full quarter teaspoon (1/4 tsp) per cup of gel. You will have a much more accurate preserving experience if you weigh your gel, do the math, then weigh your preservative accordingly. It is difficult to weigh out grams on an inexpensive kitchen scale - you need one that reads at least "0.00" or gives you 2 decimal places.
Here is the math: weight of gel in grams x % preservative recommended by manufacturer in decimals. For example, your gel ends up weighing 236 grams and you're using 1% preservative. Multiply 236 x 0.01 = 2.36 grams.
If you must "fudge" and use measuring spoons (approximate measurements, you will probably not get exactly this percent using a measuring spoon):
1/4 teaspoon per full cup = 0.5%
1/2 teaspoon per full cup = 1%
Ideally, we subtract the weight of each additive from the total when formulating products (add one gram preservative, subtract one gram gel). If your product goes funky because the measuring was off - don't say I didn't warn you. Just don't use it! And if you make a product to give a friend or family member - please use a preservative. Friends don't let friends use contaminated hair gel.
©Science-y Hair Blog 2013
The scorecard (hits, misses, and so-so):
Hit!
Preservative: Refrigeration: Regardless of the additive (agave nectar, oils, protein, thickeners), refrigeration for up to 2 weeks prevents or effectively inhibits the growth of bacteria and fungi to the point at which they are scarcely present. If you don't use up a batch of gel in 2 weeks and you're not using a commercial preservative, freeze half.
So-so (at room temperature):
Preservative: Citric acid (1/8 tsp), potassium sorbate (0.2%), vitamin E (0.2-0.3%): This may work for you, but when I tested it for bacteria, I found small quantities of bacteria and lesser amounts of fungi at 2 weeks time. The gel had begun to look cloudy. The citric acid discourages some species of bacteria, the potassium sorbate inhibits fungal (mold) growth (and you could double the amount of potassium sorbate). But this won’t preserve for a long time. If refrigerated, this preservative combination is perfectly adequate.
Hit!©Science-y Hair Blog 2013
Preservative: Citric acid (1/8 tsp), potassium sorbate (0.2%), vitamin E (0.2-0.3%), EDTA (disodium or tetrasodium EDTA) at 0.2%: This appeared to have very good preserving qualities with virtually no bacterial or fungal contamination at 2 weeks at room temperature or refrigeration. EDTA is not only an antioxidant, but it inhibits cell wall formation in bacteria. 2013 update: The pH of this may be a bit low, start with much less citric acid, adding a little at a time and use pH strips to make sure the pH is above 4.5.
Miss©Science-y Hair Blog 2013
Preservative: Cosmocil CQ (Polyaminopropyl biguanide, 0.5%) and potassium sorbate (0.2%): A very mild (to the skin) preservative which must be paired with another preservative to inhibit fungi (mold). Not a good result. The preservative made the gel look cloudy and thicker from the beginning, and there was a film over the surface at 2 weeks in the un-refrigerated sample which appeared to be mold. I was not able to identify what sort of mold. No bacterial growth was evident, and the percentage of potassium sorbate could be increased – but this preservative made an aesthetically and texturally unpleasing product from the start, thus is was a “miss.”
Hit!©Science-y Hair Blog 2013
Preservative: Sodium Hydroxymethylglycinate (0.5%) and citric acid to balance the pH:
There was no evidence of bacterial or fungal contamination in the refrigerated or unrefrigerated samples. The gel was crystal-clear and the preservative did not change the texture or thickness.
A word of caution: this preservative is a potential formaldehyde releaser and may irritate skin which is sensitive to formaldehydes. I can tolerate it, although I cannot tolerate other formaldehyde releasers, so to each their own. This preservative raises pH and it is necessary to bring it back down with citric acid so that it is not damaging to the hair.
Hit!©Science-y Hair Blog 2013
Preservative: Optiphen Plus (Phenoxyethanol, Caprylyl glycol and Sorbic acid, 0.5%):
This preservative may not work well if you use hydroxyethylcellulose in your gels (it may be rendered less effective). I have not tested this for bacteria yet, I am sensitive to this preservative. I have used it in other products and I know of another person who used it in a complex flaxseed gel mixture with no evidence of contamination after almost a month. Contaminated flaxseed gel has the advantage of becoming cloudy at low contamination levels. Optiphen Plus makes thick polysaccharide gels like flaxseed gel slightly less stringy (alters viscosity when added). It is a broad-spectrum preservative effective against bacteria and fungi.
Other preservatives I have not tested (that gets expensive!) which should be compatible with homemade gels so long as you are not adding any commercial conditioners (and possibly cellulose derivatives) are: Tinosan, Phenopip, Germall Plus, Germaben, and Geoguard Ultra.
If your homemade natural hair gel becomes cloudy, changes color, changes odor or viscosity (thickness, texture), throw it out!
On the Go: If you are away from home, no matter how well you’ve preserved your product, it should not be left in a hot car or in the sun. An exception would be putting a single-use of gel in a small bottle in a gym bag or purse to use that day. My travel tip is to bring along a cooler and stash the gel in there (along with food – hey, I travel cheap)! If you are flying or taking a train, you can stop at a store at your destination and purchase a small cooler (even a large, insulated coffee cup will do if you pack some ice around your bottle of gel).©Science-y Hair Blog 2013
A note about additives and grapefruit (seed) extract:
If you use ingredients such as prepared protein additives, these are pre-preserved. But don’t count on the preservative in there to protect your product. It may help a little, but it’s not enough.
Grapefruit seed extracts have not been demonstrated to be true preservatives. Sometimes they work because of the preservatives added to the grapefruit seed extracts to keep it from going bad (said preservatives are usually not on the product label), but don’t trust these products to keep yours from becoming home to colonies of bacteria and fungi. If you want to use grapefruit seed extract, buy it from a cosmetics-ingredient supplier so you are getting a concentrated product meant for preserving cosmetics. If the bottle says it's safe to ingest, it is probably not going to preserve your hair products for very long.©Science-y Hair Blog 2013
Clean Bottles!
When you’re done with your gel, if you wish to re-use the container, wash it well with soap and water (and a bottle brush if you have one), then use diluted bleach or rubbing alcohol (or un-diluted white vinegar) to sterilize. Pour a little in the bottle, cap it, and shake it up. Leave the bleach or alcohol in there for 20 minutes, shaking several times during the interval. Run some disinfectant through the cap if it’s a flip-cap. Then empty and rinse.
Here is a link to a post about cleaning bottles for your homemade gel.