Is foam intrinsically important to the dish-cleaning process, or is this just a correlation?


I’ve noticed when cleaning dishes that when the cleaning solution is “sudsy,” cleaning seems to happen more quickly (less scrubbing, etc.).

Is this because:

* The suds themselves help with cleaning
* The suds don’t help with cleaning but they indicate that the cleaning solution has a particular desirable property;
* The suds don’t help with cleaning and aren’t related to any desirable property.

A related question is: For any effective cleaning solution can one create a cleaning solution which is just as effective but has very little sudsiness?

In: Chemistry

The perception is that more suds equals a better cleaning product. Have you ever heard of dish detergent being phosphate free? It’s because some companies in the past added phosphates to make better bubbles and the bubbles are terrible for the environment.

Suds don’t help, they’re a product of the types of detergent used.

There are more effective detergents that don’t suds up – if you have a dishwasher it probably uses some version of these. Manufacturers tried to market them for hand washing dishes a while back but everyone kept using way too much while still not believing their dishes to be clean, because they weren’t getting any suds from it.

For most of human history, suds were a byproduct of the property that made soap work well. Around WWII, households started using more detergents, which don’t require or create suds, and they are only there so people trust it’s working.

It’s nothing about the suds themselves exactly, it’s just that the surfactants and other detergent components which are effective at dissolving lipids, aka grease/fat/oil and other substances, also happen to have a chemical structure which makes them viscous or “thick” which allows them to more easily form pockets of film which trap air, aka bubbles. Some cleaning chemical might release their own gases as well when agitated or exposed to the air, like expanding insulation foam or when exposed to other substances while cleaning things. But even so, the bubbles are just a byproduct of physical agiation and/or chemical reactions, rather than actually being a crucial function.

Bubbles are made by surface tension.

Oils disrupt this surface tension.

Therefore, if you can foam, you have not overwhelmed the properties of the detergent.

This also applies to shampoo and bath soap: if your hair is very dirty, you will never be able to lather-until you rinse the first run of shampoo off and start again. “Lather, rinse, repeat” is a joke: if you can achieve lather, there is no need to repeat.

Your last question is an emphatic yes: nonsudsing dish detergents are a thing. It’s called “dishwasher detergent”. This is by design, especially for use in high pressure high speed machines. Use a foaming soap in something that is putting forth much more power and speed than human arms can, and you will end off with a [foamsplosion (jump to 15:00)](

To corroborate the other comments, there are in fact chemicals and stuff added to make suds specifically because of the generally false notion that suds equal *cleaning*. I actually had an Environmental Toxicology course that focused heavily on that sort of stuff, along with things like microplastics from the little scrub beads that get washed down the drain and stuff.


I do also want to reiterate what u/Ishidan01 said, because that is also true. Suds forming can be an indication that you aren’t doing too much, or have successfully cleaned something.