In a previous post, I revealed how astonishingly easy it is for me to be amused. By handsoap. No, I'm not Patrick, SpongeBob's brainless, starfish friend, but I have pursued my attempt at homemade foaming handsoap one step further.
My first recipe is as follows:
palm oil, 150 g
coconut oil, 50 g (both oils melted in a ca. 600 mL glass bottle)
water, icy cold, 240 g
potassium hydroxide, 90% w/w, 42 grams
I mixed the KOH with icy water (very exothermic and the icy water makes this part pretty non-smelly, resulting solution about 100-deg-F). Then I added it to a mixture of palm and coconut oils (melted and cooled to ca. 100-deg-F) and added some more water (ca. 100 mL) and shook the crap out of it. It was initially pretty lumpy and two phases. (I think I'd use an immersion blender next time.) For the next day, I shook this high tech glass mixing jar (old mayo jar, Hellman's) and let it set with the lid loosened (just in case the mixture got exothermic or something) and placed the entire jar inside a deep plastic bowl (just to contain anything unexpected). Within several days of leaving it alone, the resulting solution became homogeneous with a bunch of foam sitting on top.
So far, there's roughly 200 grams of solid soap in this mixture (roughly the amount of fat used). After some reading, foaming hand soap is mostly a result of the dispenser, but, equally important, it needs to be pretty dilute; somewhere between 4-10% solids by weight. If I shoot for a first guess of 5% solids (w/w), this would dictate taking this mixture and diluting it (ideally in deionized water) to a total weight of 4000 grams (roughly a gallon). I'm going to let it sit a while longer. After Easter, I'll dilute it and put it in bottles (I scored 5 of those pump bottles on ebay this morning for about a buck each, including shipping) and will let you know the results.
I'll probably also scent the mixture with lemon verbena essential oil if the soap foams nicely (not going to waste it until I know it works).
Parents of small children, you may be reading about the development of your xmas present.
Where to buy stuff:
1. Oils can be purchased here.
2. KOH can be purchased at the Science Co.
3. Hellman's Mayo can be purchased at Giant Eagle, but you have to eat 600 mL of it or dump it in the drain and use the bottle.