How to choose between commercial liquid soap and foam soap I Dolphin Solutions

04 August 2022

Reading time: 7 minutes

Deciding which soap is better for use in a commercial washroom is often met with questions about the hygiene properties, which soaps to avoid, the cost difference, and whether the soap will suit the chosen soap dispensers.

The result of choosing the incorrect soap introduces the risk of dealing with ongoing maintenance issues, health hazards, unsatisfactory user experience, and uneconomical usage. Before signing a contract with a soap supplier, you should familiarise yourself with the most appropriate and commonly used hand washing soaps for commercial washrooms and understand the advantages and disadvantages.

With over 23 years of experience in the commercial washroom industry, Dolphin provides hand washing soaps containing the perfect balance between hygiene and suitability. We will help you decide which soap is best for your washroom by explaining the difference between commercial liquid soap and foam soap, hygiene properties, WELL compliance, user experience, the fusion with soap dispensers, and cost.

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What is the difference between liquid soap and foam soap?

In their raw form foam soap and liquid soap are both liquids, with foam soap having a very low viscosity, similar to water. Liquid soap has a greater viscosity and resists motion more than foam soap due to its strong molecular makeup. Viscosity is the measure of a liquid’s flowability – lower viscosity equals more flowable liquid i.e. more runny.

The main difference is when the soap is pumped out of a dispenser. Foam soap is forced through a gauze by compressed air which infuses the air with the soap to create the rich bubbly lather that comes out of the dispenser nozzle. Liquid soap merely passes through the nozzle in its raw form with no transformation.

Which commercial soap is more hygienic?

Soap physically cleans away the debris on one’s hands by the compounds in the soap working together to remove germs and dirt, then washing it away with water. Determining the ultimate hygienic soap depends on the level of soiling to be removed, the environmental factors of the washroom, and the cleaning procedure of the soap dispenser and feed.

How does the soap system cleaning procedure affect the anti-bacterial properties of soap?

If the reservoir is not cleaned effectively – WELL requires bulk reservoirs to be removed and sanitised between each refill – there is a risk of bacteria growth overwhelming the bactericidal properties of the soap. Foam soap will start to congeal in the reservoir causing blockage in the dispenser and eventually in the whole supply system. This has major maintenance implications. With liquid soaps, bacteria usually causes the soap to become very runny frequently causing the soap system to require priming after a period of inactivity.

Fortunately, because cartridge soap systems are sealed, the risk of bacteria infiltrating the system and contaminating the soap is highly unlikely or not at all possible.

Which commercial soap complies with WELL standards?

The bottom line is – regardless of whether the soap is liquid or foam, to stay compliant with the WELL standard, an odourless liquid hand soap (which includes foam soap) must be used in all soap dispensers, and any bulk reservoir must either be sealed, as in a cartridge system, or the reservoir must be removed, flushed and sanitised before each refill.

Liquid soap or foam soap user experience

Is there a difference in user experience?

The best soap comprises a delicate balance between consistency, anti-bacterial properties, abundant lather, the right amount of skin nourishing oils, and a neutral pH level. It should not possess skin irritant properties or high acid content to impact the user experience.

Liquid soap typically comes out onto a user’s hands in a thick heavy blob and tends to have added moisturizers that need a little more effort to wash off. But there are liquid soaps that dry out and chafe a user’s hands due to the harsh chemicals in the liquid, and these are the ones you want to avoid purchasing.

It is a popular option, but if you want to choose an appropriate liquid soap for your commercial washroom, then Pink pearl soap is a winner as it comprises just the right amount of all the elements for a pleasant hand washing experience.

Foam is much easier to wash off because the volume of raw soap is much less, typically just 0.3ml, but is aerated when dispensed to give a good user experience and comprises more water content in its molecular makeup. The viscosity is much lower than liquid soap, similar to water, and spreads further on a user’s hands. The reduced volume of foam soap, easier lathering and the washing-off process save the precious commodity of water and energy – water saved does not need to be heated.

Can liquid soap and foam soap be used in all commercial soap dispensers?

Yes, manual and touch free soap dispensers can hold foam or liquid soap, but foam soap requires a special valve to create the foam and selecting the correct soap dispenser to match the soap is essential.

Pink pearl soap is a favourite hand washing liquid soap choice for manual and sensor soap dispensers because its viscosity is the ideal balance between runny and thick giving optimal performance. It is renowned the universal liquid soap for all commercial washrooms soap dispensers. Its flowability allows it to move from the reservoir to the outlet with minimal resistance, whilst its viscosity helps reduce the risk of drain-back in the supply tube that would otherwise require the dispenser to be primed after periods of inactivity.

Foam soap is best suited for multi-feed systems where one reservoir supplies several dispensers because it has a low viscosity and is gravity fed allowing free movement of the fluid over large distances. How a cartridge soap dispenser system works enables the foam soap to pass through the feed with no resistance and reduces the risk of blockage through the sealed system. In cartridge soap dispensers, it is recommended to only use foam soap rather than liquid soap due to the longer feed from the reservoir, which requires a low viscosity soap.

Which soap is more economical?

Foam and liquid soap generally cost the same, but some suppliers sell their liquid soap for less. However, foam soap uses less product per use compared to liquid soap and achieves the same result during hand washing, so less frequent purchase orders are needed to replenish stock because the foam soap lasts longer. Ultimately, you spend less time ordering refills and less money over time because it is long-lasting.

Which soap should you choose?

As both commercial liquid soap and foam soap have unique characteristics, you should base your decision on the following:

Anticipated replenishment interval
Individual dispenser reservoirs or multi-feed supply
Type of soap dispenser (manual or sensor)
Cost and budget
Compliance with WELL standard
Anti-bacterial properties
Good user experience
Cleaning and maintenance procedures

The considerations above will narrow your choice of dispensers and help you decide what type of soap you require, ensuring you have matched the two before signing that contract with a soap supplier.

How to choose between commercial liquid soap and foam soap