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March 19, 2007

Homemade Foaming Handsoap - Part I (in an occasional series)

I don't think there's a more simple pleasure than foaming handsoap. Sounds silly, but compared to the drizzly liquid non-foaming soap, it's a party. And, when you have a young child, you realize washing your hands obsessively can be the difference between having a normal life and being sick for large chunks of a year at a time.

So, I've been cruising the net looking for why soaps foam and how to make my own and believe it or not, the only reasonable links I've found to attempt to make my own is from Cockeyed in this and this post! These links imply it's all in the dispenser, but I'm still hunting down the reason. If these Cockeyed expts. are valid, it's going to be amazingly inexpensive to refill a typical foaming handwash dispenser.

I'm still searching for why these work (if this is the case) and will keep you posted.

Also ...
Fun expt link for a foaming soap.

Found what I needed:
Foaming Soap Patent, a calculator for concocting a liquid soap formulation, in the patent is a dilution factor and finally, all I need is a pump (or a recycled one that we already purchased) to make it foamy. It's actually the pump that makes the liquid soap foamy!

... to the lab.

The potassium hydroxide's been ordered and the recipe formulated. Stay tuned for the recipe.

First attempt recipe: not done yet (3/28/07)
palm oil, 150 g
coconut oil, 50 g (both oils melted in a 2L plastic bottle)
water, icy cold, 240 g (and eventual dilution to 2.0 L)
potassium hydroxide, 90% w/w, 42 grams
lemon verbena scent, 10 mL (added after saponification)

Intended procedure:
-add KOH to icy water (very exothermic process, icy water keeps fumes minimal), let cool to ca. <100-deg-F
-melt oils in hot water bath in 2L soda bottle
-charge KOH/water solution to fats and wait until the resulting solution is homogeneous (saponification finished)
-add essential oil, dilute to 2L with distilled water, mix gently, done.
-refill dispensers with el cheapo liquid soap

Don't miss the breathtaking Part II in this series ...

Part I
Part II
Part III

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Anonymous said...

Wonder if Cockeyed had used distilled water or had boiled it first if he would still have had the slime problem? Doesn't say much for the quality of his tap water should that solve the problem.

Dave said...

I think, simply not cleaning out the dispenser between charges could've easily caused this. The water content is so much higher in these formulations and is more susceptible to mold formation.

Anonymous said...


I'm no scientist. However, I also like the foaming soap. I purchased a bottle of it to dispense out of my kitchen sink soap dispenser. I poured it into the dispenser bottle, screwed it back in and out came liquid it has to be all in the dispenser.

Dave said...

Hey Maria,

Thanks, saves me an experiment.

I've been hunting all over the place and EVERYONE uses the same 7.5 oz. dispenser for the foamy soap. I found a place I can order them. Unfortunately, I have to order a minimum of 25,000 of them. I think I'll reuse the container I got from Target a while.

Dave said...


If you look at those new foaming dishwashing detergents, you'll notice they have an unconventional cap. This and the handwashing foam pump (cap) basically pre-lathers a MUCH more dilute soap by adding a lot of air to it as it's delivered from the nozzle. So, what I've found, is you're spot on. The foaming is a product of the packaging (and it requires the soap to be much more dilute).

So, while it's a nifty device, it's also much more expensive. But cool nonetheless.

I'll post my recipe for pump soap when I get all the ingredients and make up a batch.

Miss Lexiloo said...

This is an interesting experiment. I also love foaming soap. I've gotten to the point, in fact, that I don't use regular hand soap at all at my house. It seems so slimy now.

However, Dial offers huge refill bottles at Walmart, so I go that route.

Dave said...

It's probably a better route. My experiment was silly, I'm a frustrated desk-bound chemist, so I couldn't help trying to make it.