A Guide to the Formulation and Ingredients of Dishwash

What makes dishwash effective?

It’s a kitchen essential, but you may not have thought much about what makes dishwash so much better than just using hot water. 

The best dishwash is powerful enough to cut through the dirt, grease and grime that sticks to kitchenware, while being easy to use and cost-effective. A good amount of foam saves you from using too much liquid, so your bottle lasts longer.

We’ve created this guide so you know exactly what goes into your dishwash and what makes some liquids more effective than others.

The ingredients in dishwash

Water

Water is the main ingredient in dishwashing liquid. It is a ‘universal solvent’, meaning water dissolves more substances than any other liquid. It’s a good cleaning agent by itself, but when water is combined with detergents and surfactants, it becomes a very effective dishwashing liquid.

Detergents

Detergents are the main ‘active’ ingredient that makes dishwash an effective cleaning product. In this case, ‘detergent’ is a synthetic cleaning compound used in dishwashing liquid instead of soap. 

Soap can react with minerals like calcium that naturally occur in water and form soap scum, creating another job to clean up. Synthetic detergents give a great clean without the messy side effects.

Surfactants

Surfactants decrease the surface tension between two substances - or in simple terms, make cleaning dishes easier by breaking up the food and dirt stuck to them. 

Detergents are synthetic surfactants. Most dishwashing liquids contain synthetic detergents and organic surfactants for the best cleaning capabilities. For instance, ethanolamine is a naturally occurring surfactant common in cleaning products for its effectiveness in removing dirt, grease and stains from clothes and surfaces.

Surfactants often have foaming properties, allowing the liquid to sit on surfaces for longer and giving your dishwash extra cleaning power.

Thickening agents

Have you ever used a dishwashing liquid that feels too ‘thin’ - more like water than a gel? It’s likely that the liquid didn’t have enough thickening agent in the mix.

Thickening agents are added for ease of use. They don’t directly add any cleaning ability to dishwashing liquid, instead making it easier for you to control its application. 

Stabilising agents

Mixing several detergents, surfactants and thickening agents together with water doesn’t mean that your dishwashing liquid will work. It’s likely all the chemicals will separate easily and, without some extra help, won’t mix well.

Stabilising agents are the glue that holds the dishwashing liquid together. They ensure that the liquid has a consistent thickness and that the cleaning agents are evenly spread through the bottle. Some stabilisers will also act as foaming agents.

Fragrances

The final touch to a great dishwashing liquid is the smell. 

Some dishwash liquids contain natural fragrances, which can help with cleaning. Concentrated lemon juice is common, providing a great fragrance and containing citric acid, a natural cleaning agent that helps remove tough stains.

In most cases, fragrance adds nothing to the cleaning ability of dishwash, but a nice smell of something like lemons adds that finishing touch to a pile of clean plates - a sign of a job well done.

The common ingredients in dishwash - and some warnings

Dishwash is made up of synthetic and organic chemicals, and not all of them are friendly to humans or the environment.

Protecting your skin is obviously important. Some dishwashing liquids contain irritants or dangerous chemicals that you and your staff should be aware of and protected against. So long as you take the proper precautions - wearing gloves, not touching your face when washing up - your staff should be protected against harmful effects.

Issues like wildlife toxicity to issues at water treatment plants also make some chemicals dangerous to the environment. As hotels globally move towards more sustainable practices, it’s worth bearing in mind the ecological impact of the dishwashing liquid you use.

This is not an exhaustive list of chemicals found in dishwash, but rather some common examples:

Sodium laureth sulphate: This is one of the most common chemicals found in dishwash. It’s a detergent, surfactant, and an effective foaming agent. However, sodium laureth sulphate is also an irritant, so anyone using it must rinse plates off after washing them to ensure no chemicals are left behind.

Formaldehyde: Formaldehyde is added to cleaning products to prevent bacterial contamination and as a preservative. However, it is carcinogenic and an irritant, so you should take every possible precaution when using dishwash containing this chemical.

Methylisothiazolinone: A synthetic chemical, methylisothiazolinone is used for its antimicrobial properties and as a preservative. While it extends the shelf life of cleaning products, there are links to allergies and issues like dermatitis eye damage. 

Sodium dodecylbenzene sulfonate: This is a surfactant used in many cleaning products as a surfactant, helping break up dirt and food particles more easily. It is a skin and eye irritant.

Sodium xylene sulfonate: Commonly used in heavy-duty degreasers, dishwashing liquids and shampoos, sodium xylene sulfonate is a surfactant. It causes serious eye irritation and is a skin irritant that potentially causes respiratory irritation. If your dishwashing liquid contains this chemical, make sure you wear the appropriate protective clothing.

Sulfonic acid: Sulfonic acid is a surfactant that is very effective at breaking down the barrier between water and dirt or grease. It’s one of the most popular surfactants used in cleaning, but is also an irritant.

Triclosan: Triclosan is used in a range of household items, including soap, toothpaste and detergent. It’s an antibacterial agent, making triclosan a useful addition to cleaning products. However, concerns are arising over the potential for antibiotic resistance and a possible link to disrupted hormonal development. 

As such, the FDA in the US has banned its use in household soap products and restricted companies from using it in over-the-counter antiseptic products without a pre-market review. In Europe, the EU has put triclosan on a list of substances to be replaced.

Phosphates: These are becoming increasingly rare in dishwashing liquid because of some significant issues. Phosphates make detergents more effective, but they remain in wastewater. When this water eventually reaches natural bodies, the phosphates feed algae and can cause harmful algae blooms. 

There are a lot of complicated names in dishwashing liquid. As we’ve said, you won’t have to worry about most if they are used in your chosen brand, so long as you take the proper precautions when washing up. So, make sure your staff wear gloves and keep the liquid away from exposed skin and eyes.

Putting it all together

Different detergents and surfactants in varying amounts mean retailers can tailor their dishwash for different purposes. You might see dishwash that’s less effective at cleaning tough stains, but is cheaper than a formulation that cuts through tough grease.

The main ingredient in dishwashing liquid is water. Because the content is so high, there’s no need to dilute it further with water - simply apply the gel to the surface that needs cleaning and get scrubbing!

But what happens when all these chemicals are combined?

Dishwash is so effective because the solution contains molecules with opposing properties. One side is ‘hydrophilic’ - this loves water. The other end is ‘hydrophobic’ - this repels water. The hydrophobic end clings to grease and dirt, while the hydrophilic end pulls the molecule (with the grease attached) away from the surface. This bit of chemistry is what cleans your plates!

How effective is your dishwash?

Not all dishwashing liquids are created equal. 

As mentioned above, different dishwashing liquids have different purposes. While reputable dishwash brands will all clean to a certain minimum standard, specific use cases may require you to look at the cleaning properties to find the right solution for your needs.

For particularly tough grease stains, you’ll likely need to look at dishwash that contains stronger surfactants. However, even strong dishwash won’t be as effective on accumulated stains found on baking trays, pans and inside ovens - it’s recommended you use a dedicated degreaser for those tougher jobs. 

While dishwash has a long shelf life, it doesn’t last forever. For instance, Vim hand dishwash has a maximum shelf life of 24 months. Dishwash isn’t perishable like food, but its effectiveness does decrease over time. In particular, the bacteria-killing properties will fade over a couple of years, eventually rendering the liquid useless for deep cleaning. 

It’s important to keep an eye on the expiration date of your dishwash, and prepare to replace any nearing the end of their shelf life.

When buying dishwash, look at the thickness of the liquid. Those that are more gel-like are easier to apply. In addition, look at dishwash with good foaming capabilities - lots of foam means you don’t need to use as much liquid.