This recipe makes a lotion which feels light, spreads easily and is not greasy at all. The smell is actually pleasant, and it works really well against insects AND the sun. I can't give a precise SPF value -- that depends not only on how thickly it is spread on, but also the strength of the various ingredients which contribute to the SPF varies from batch to batch. Anyway the SPF value does not have much concrete meaning.... What I can say is that a few weekends ago I took my family to watch Prince Harry play polo on Governor's Island for an hour under a punishing sun, and none of us got burnt or bitten. Other spectators were not so lucky....
Thanks to Scoochmaroo for inspiring me to publish this. Her sunscreen is quite different from this one (very thick and stiff -- but also a whole lot less complicated) so I though it worthwhile to offer this alternative.
Step 1: On Sunscreens
Sun rays, just like any other type of waves (water, sound, etc) come in different lengths. The short ones are called UVB. These are the waves which give you sunburns, and, on the positive side, prompt skin to produce the vitamin D we all need. SPF ratings on commercial sunscreens measure the cream's ability to block these waves, and these waves only. It indicates roughly how much more time you can spend in the sun before burning, but it tells you nothing about your protection against UVA rays.
UVA rays are much longer waves, and therefore they penetrate deeper into the skin. These are the rays responsible for the telltale signs of aging, and also for the #1 killer skin cancer, melanoma.
Some ingredients, such as zinc and titanium oxide provide "broad spectrum" protection, which means they block both UVB and UVA rays. These chemicals protect the skin by deflecting and diffusing the waves, but their drawback is that they make skin white when they are first applied. To counter this manufacturers have developed nano zinc and titanium particles which don't make you turn white. Unfortunately, since they are so tiny, they can penetrate into the bloodstream, where the damage they could wreck has not been studied. Unless you want to be part of a long term, unpaid, unmonitored medical study, avoid nano particles. Don't be so lazy and vain. Take a minute to rub in the regular zinc oxide, after a while you won't look like a zombie. I avoid titanium dioxide because it is carcinogenic (for sure on mice, possibly for us too) -- so why take the unnecessary risk when zinc does the job just as well?
Step 2: Ingredients and Where to Find Them
1/3 cup witch hazel (or 5 tbsp if you do not use coffee)
2 tsp fresh coffee grounds (optional)
1 tbsp coconut oil
1 1/4 tsp ewax
1/2 tsp Neem oil
1/2 tsp sesame oil
2 tsp cocoa powder (optional)
1 tbsp zinc oxide (quantity can be doubled for extra protection)
1 small pinch xanthan gum (do NOT omit)
1/2 tsp turmeric (optional)
1/4 tsp vitamin E
1/4 tsp essential oils (combination of citronella, eucalyptus and lavender, but pennyroyal and peppermint can be used too)
Note on ingredients:
Coconut oil, sesame oil, vitamin E, zinc and turmeric are all "sun" ingredients. Turmeric (a yellow spice you'll find in any supermarket) was used as a cure all in Ayurvedic medicine, but since those guys also believed diseases were caused by demons and that you can wish yourself not to age, I included it here for other reasons: #1 color. I prefer to look sickly yellow rather than zombie white (the coffee and cocoa are also here to improve the color). #2 according to wikipedia turmeric is used in sunscreens and to protect foods from sunlight. If it keeps a pickle nice and firm, hey, maybe it'll keep me from getting flabby! Now I'll just close my eyes and wish for eternal youth...
Neem oil, witch hazel and the essential oils are the bug ingredients. Neem is a potent, dark oil which in this diluted form is safe (and good for) your skin, but it should be avoided during pregnancy. Neem has a distinctive smell somewhere between garlic and peanuts. Unpleasant at first, but it grows on you. It's kind of comforting, like the smell of farts under bed covers.
Xanthan gum is necessary for three reasons: it thickens the lotion so it will not run all over when you try to apply it. It stabilizes the emulsion (keeps the water from separating), and it keeps the zinc oxide suspended in the lotion. Don't be fooled by the small quantity required: you need it.
Ewax is another crucial ingredient. The E stands for emulsifying, and it's purpose is to blend the oil and water into a smooth, stable cream (you might find it under the name "emulsifying wax NF" in online stores. It comes in white, waxy flakes which are easy to measure and melt. It is not considered "all natural" because it is composed of a blend of cetearyl alcohol and polysorbate 60.
Soap Goods supplies all the above ingredients and it might be easiest just to order everything from them, but I found my xanthan gum in the vitamin section of my local Fairway for less (however considering the time spent searching, and the cost of transportation, the savings, if any, are negligible). I would definitely buy the witch hazel from a local pharmacy, and the coconut and sesame oils from a grocery store because they are widely available and heavy to ship.
Step 3: Mixing and Bottling
Meanwhile sift the powder mix together.
Remove the witch hazel mix from heat. If you used coffee pass the liquid through a paper filter and add an extra tablespoon of witch hazel.
Slowly drip the oil mix into the witch hazel, blending with a fork or milk frother till all the oil is mixed in and emulsified.
Blend in the powder mix, then the additives.
Step 4: Use and Warnings
I once came across a ridiculous web page written by the Soap and Detergent Association, clearly on the defensive about the rise of DYI -- but one point they made about labeling really does make sense. It is dangerous to have ANY sort of chemical product mislabeled in a recycled container. It is important not only to remove the old labels but also to put on your own, preferably with a detailed list of all the ingredients and first aid instructions in case of accidental misuse. So if you try out my recipe, please print the attached PDF file and use the label (or design your own if mine isn't colorful enough -- I designed mine to look as dull at the real ones).
Warning for people with allergies or sensitive skin: do a patch test before slathering this on. It is quite possible that you would tolerate Deet much better than this -- after all, the vast majority of allergens are 100% natural, 100% organic. Think pollen, dander, nuts, strawberries, mildew.... To test individual ingredients, mix them with something you won't react to (like good old synthetic vaseline) in a concentration roughly equivalent to the concentration in the recipe (1 drop of essential oil mixed with 1/2 tsp mineral oil or vaseline, for example) and dab that in the crock of your arm. For extra peace of mind, do this every day for 2 weeks to make sure you will not become sensitized over time.
A final note on longevity -- it is impossible to give a definite shelf life time frame because too many factors are in play. The first and most important factor is how well all the containers, tools and fingers which come into contact with the product have been sanitized. Ideally, dunk everything (except for fingers) in a pot of simmering water for 15 minutes. That's how I do it when I make jam, but it's not always practical for lotions (the recycled PET containers I use tend to get deformed at those temperatures...). Just clean everything as best you can. Another factor is how fresh your ingredients are. Still another, what ingredients you choose (my coffee/cocoa version, for example, might have a shorter shelf life than the version using straight witch hazel). Finally, whatever spore is floating around in the air or organism is living on your fingertips when you open the bottle might jump in and start a thriving colony.... This is why I usually make small batches or use preservatives. That's right. There's nothing wrong with adding a small quantify of preservatives, in fact, I highly recommend it if you are making any lotion as a gift. I have used Liquid Germall Plus, a paraben free preservative which seems to work quite well. All you need is 0.1 to 0.5% of the total weight, which translates for this recipe to about 3 drops.
Step 5: A Note on the Cost
To see what other projects I'm cooking up, check out my blog, www.makeanything.net