April 11, 2010 - I corrected the % and calculated grams amount of oil which were mistyped as 4% and are now correct at 16%.
It seems sunscreen is a hot topic these days. Which brands work, which brands are more natural, which brands don't aggravate eczema, acne, etc. Then if you're considering a more natural but effective sunscreen you could end up paying an arm and a leg for a teensy tube of sunscreen. Who's going to slather on $20 a bottle sunscreen?
Fear not! You can make dare I say even better sunscreen at home without having to change out of your PJs. Oops, I said that out loud huh? I've mentioned before that the Wabi Sabi blog has been invaluable for information on making lotion and now sunscreen. I tinkered with my lotion recipe but simplified it a bit to a jojoba/water emulsion. Then I chose to start off with the minimum recommended amount of zinc oxide - 7% to see if it would be something I could use on my face (which in case you're wondering is not white thus the perfect litmus test).
I bought micronized zinc oxide from Garden of Wisdom. I know some people are concerned about micronized particles but I've read a bit, just enough to convince me it's not a great concern. Have to pick your poison, right?
Marielle's Homemade Suncreen
note: Again with the scale, but I don't mix bread or beauty products without my trusty scale. Too much margin for error and I'm a very picky customer.
78.5% Water - brought to a boil
16% jojoba oil
2% BTMS emulsifier
1.5% Cosmocil CQ - a preservative
that makes for a 100% lotion formulation, then I calculate 7% of that weight for the zinc oxide amount. And people said you don't use math everyday. Pshaw!
Here's my math for this 6oz batch of sunscreen (two 3oz bottles). When I calculate I do it in decimals but when I weigh out ingredients I do it in whole grams.
6oz = roughly 170 grams
143.65 grams water
27.2 grams jojoba oil
3.4 grams e-wax
3.4 grams BTMS emulsifier
2.55 grams Cosmocil CQ
Then 7% of 170 grams is 11.9 grams of zinc oxide.
First boil your water and then melt your oils and waxes together.
My sunscreen mise en place. My hot water, the oils/waxes, cosmocil (clear fluid in the rear custard cup) and the zinc oxide. Making lotion is a pretty fast process. Just make sure the water and oils are still hot in order to emulsify well.
Add the hot water to the oil/wax mix (the oil phase) and instantly the mixture will turn a milky white.
You can either mix it by hand (I'm using a butter knife) or a stick blender. I've done both. However, the stick blender tends to aerrate the mix more quickly and makes a thicker lotion right away. I wanted a thinner liquid while warm for easy pouring and the sunscreen will still thicken as it cools.
Give the mix a good stir. Then let it cool just a bit. My preservative - the cosmocil - has to be used at temps below 176 degrees fahrenheit so I let the mixture cool just slightly (still hot) then mix in the cosmocil.
Immediately after the preservative while the mix is still hot I stir in the zinc oxide. Surprisingly the powder mixed in very well. I let the sunscreen cool to a moderately warm tempeture then I'm ready to bottle.
I bought these bottles at Wally World for a buck each. They're called Malibu bottles and are also available online. They are very similar to commercial sunscreen packaging and great for dispensing lotions since the cap is on the bottom.
Pour in the sunscreen and get your super fancy label on there. I know, someone as OCD as me should have some kind of PDF printable, gussied up label for her beauty products. No thanks. Masking tape and a sharpie. Easy to get on but most importantly, easy to get off. I just write the date, the percentage of zinc oxide and the main emollient ingredient (jojoba) so I remember for next time.
While the sunscreen is cooling, shake the bottle every five minutes or so. This will ensure that the zinc oxide stays suspended until the lotion sets up after it cools. That's it. Homemade sunscreen.
A test patch on my skin. A swipe of sunscreen above, then a swipe of blended sunscreen right below. No white cast. The true test would be on my face. That day I applied a full face of sunscreen and blended it very well. Despite my blending there was just the teensiest bit of lightening on my skin. But you should know that I'm super picky about shade fluctuations on my face. I use mineral makeup that I get custom blended by Rhonda at BareFaced Minerals. Having been a woman of color all my life it's just something I'm very aware of. If you are fair skinned, this should not be an issue. In fact, I can use this on my body and on the kids, it sinks right in without a whitish cast at all.
So I'll stick to my mineral makeup for sun protection on my face (zinc is also the main ingredient) and use this sunscreen on my body. It's very silky, again sinks right in and absorbs without feeling greasy. Very important if I wanted Mr. Maricucu to wear it while working on the yard and the boys to wear it while playing. A bonus, again thanks to info on wabi sabi, is that zinc oxide is a very soothing ingredient. Of course, it's a big ingredient in diaper rash cream and because of this, you can use the sunscreen as a cloth diaper-friendly rash cream. A multitasker, gotta love that.