# What is the difference between foaming hand soap and regular? **URL:** \ **Category:** Factual Questions\ **Created:** [April 8, 2008, 9:10pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-foaming-hand-soap-and-regular/444511 "2008-04-08T21:10:21Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [April 8, 2008, 9:10pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-foaming-hand-soap-and-regular/444511/1 "2008-04-08T21:10:21Z")
Or perhaps phrased another way: How do they make foaming hand soap foam? Is it just that it has more water in it? ---
**Author:** ![Lanzy](https://avatars.discourse-cdn.com/v4/letter/l/74df32/32.png) [@Lanzy](https://boards.straightdope.com/u/Lanzy)\ **Post date:** [April 8, 2008, 9:20pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-foaming-hand-soap-and-regular/444511/2 "2008-04-08T21:20:02Z")
My guess is more air. Bubbles. o, that WAS a guess. ---
**Author:** ![thirdname](https://avatars.discourse-cdn.com/v4/letter/t/d07c76/32.png) [@thirdname](https://boards.straightdope.com/u/thirdname)\ **Post date:** [April 8, 2008, 9:23pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-foaming-hand-soap-and-regular/444511/3 "2008-04-08T21:23:42Z")
I’ve wondered about this. I like the foaming soaps they’re using in public restrooms. I can wash quicker with them because they’re already lathered up, as opposed to a thick liquid. I’ve wondered whether they have some sort of manual air pump, or a pressurized vessel, some chemical reaction or what. Maybe just a big bag of foam? ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [April 8, 2008, 9:24pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-foaming-hand-soap-and-regular/444511/4 "2008-04-08T21:24:00Z")
They have a pump that forces air into it to make the foam. I have a refillable one at home and the instructions that came with it say to put 1 part normal liquid soap to 4 parts water. So another difference is the foaming soaps contain a lot more water. ---
**Author:** ![Maastricht](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@Maastricht](https://boards.straightdope.com/u/Maastricht)\ **Post date:** [April 8, 2008, 9:25pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-foaming-hand-soap-and-regular/444511/5 "2008-04-08T21:25:07Z")
If you mean the kind of soap that comes out the nozzle as foam, I think that is because of the dispenser, which adds air to a mixture of diluted soap. That said, some basic detergents foam more then others. The cheapest liquid detergent, which is a staple ingredient in shampoos, and other liquid soaps (and even in toothpaste) is [Sodium laureth sulfate, or SLS.](http://en.wikipedia.org/wiki/Sodium_lauryl_ether_sulfate) That one creates a lot of foam in watery solutions, so much so that when it is used in products where foam is a nuisance (like toothpaste or some types of dishwasher liquid, where foam clings to the clean glasses) it requires that an anti-foam substance is added. ETA: a lot of the liquid soap that comes out of dispensers is also watered down, but thickened up with a thickening agent. That made me feel less bad about washing globs of it down the sink. But I agree that foamed up soap is more efficient to use. ---
**Author:** ![NunOfTheAbove](https://avatars.discourse-cdn.com/v4/letter/n/51bf81/32.png) [@NunOfTheAbove](https://boards.straightdope.com/u/NunOfTheAbove)\ **Post date:** [April 8, 2008, 9:30pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-foaming-hand-soap-and-regular/444511/6 "2008-04-08T21:30:02Z")
It the SDS, or Sodium dodecyl sulfate (sometimes called sodium lauryl sulfate). It’s a pretty common detergent. Here is a wiki - > **[Sodium dodecyl sulfate](https://en.wikipedia.org/wiki/Sodium_Dodecyl_Sulfate)** > > Sodium dodecyl sulfate (SDS) or sodium lauryl sulfate (SLS), sometimes written sodium laurilsulfate, is an organic compound with the formula CH3(CH2)11OSO3Na and structure H3C−(CH2)11−O−S(=O)2−O−Na+. It is an anionic surfactant used in many cleaning and hygiene products. This compound is the sodium salt of the 12-carbon organosulfate. Its hydrocarbon tail combined with a polar "headgroup" give the compound amphiphilic properties that make it useful as a detergent. SDS is also component of mixtur... You beat me to it… ---
**Author:** ![Tastes\_of\_Chocolate](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tastes_of_chocolate/32/3232_2.png) [@Tastes\_of\_Chocolate](https://boards.straightdope.com/u/Tastes_of_Chocolate)\ **Post date:** [April 9, 2008, 2:43pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-foaming-hand-soap-and-regular/444511/7 "2008-04-09T14:43:23Z")
[QUOTE=gazpacho] They have a pump that forces air into it to make the foam. I have a refillable one at home and the instructions that came with it say to put 1 part normal liquid soap to 4 parts water. So another difference is the foaming soaps contain a lot more water. [/QUOTE] We just buy a disposable foaming soap dispenser at the store, and when it runs out, refill with liquid soap + water, rather then throw it away. In the bathrooms, it’s shower gel, in the kitchen it’s dish soap. The dish soap mix makes it really easy to clean just 1 dish or pan, without getting way to much soap. ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [April 9, 2008, 2:54pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-foaming-hand-soap-and-regular/444511/8 "2008-04-09T14:54:35Z")
Thanks guys. It seems that as usual I am guilty of phrasing my question poorly. Of course I \*get \*foam. I understand that air is injected. What I was wondering is the difference between regular liquid soap and the kind in dispensers that inject air into it creating the foam. \*\*gazpacho \*\*has confirmed my hunch that you don’t just use regular liquid soap, but instead must water it down - and has provided the ratio. My fault for phrasing it poorly.