Commercial Dishwasher Detergent Ingredients
from http://en.wikipedia.org/wiki/Dishwasher

How Do Detergents Clean?

Detergents and soaps are used for cleaning because pure water can't remove oily, organic soiling. Soap cleans by acting as an emulsifier. Basically, soap allows oil and water to mix so that oily grime can be removed during rinsing. Detergents were developed in response to the shortage of the animal and vegetable fats used to make soap during World War I and World War II. Detergents are primarily surfactants, which could be produced easily from petrochemicals. Surfactants lower the surface tension of water, essentially making it 'wetter' so that it is less likely to stick to itself and more likely to interact with oil and grease.

Modern detergents contain more than surfactants. Cleaning products may also contain enzymes to degrade protein-based stains, bleaches to de-color stains and add power to cleaning agents, and blue dyes to counter yellowing. Like soaps, detergents have hydrophobic or water-hating molecular chains and hydrophilic or water-loving components. The hydrophobic hydrocarbons are repelled by water, but are attracted to oil and grease. The hydrophilic end of the same molecule means that one end of the molecule will be attracted to water, while the other side is binding to oil. Neither detergents nor soap accomplish anything except binding to the soil until some mechanical energy or agitation is added into the equation. Swishing the soapy water around allows the soap or detergent to pull the grime away from clothes or dishes and into the larger pool of rinse water. Rinsing washes the detergent and soil away. Warm or hot water melts fats and oils so that it is easier for the soap or detergent to dissolve the soil and pull it away into the rinse water. Detergents are similar to soap, but they are less likely to form films (soap scum) and are not as affected by the presence of minerals in water (hard water).

Different kinds of dishwashing detergent contain different combinations of the items in the list below. Not all of the ingredients below are used in some detergents.

Dishwashing detergent may also contain:

Dishwasher detergents are strongly alkaline (basic).

Inexpensive powders may contain sand, which can be verified by dissolving the powder in boiling water and then passing the solution through a coffee filter. Such detergents may harm the dishes and the dishwasher. Powdered detergents are more likely to cause fading on china patterns.

Rinse Aid

Rinse aid (sometimes called rinse agent) contains surfactants that uses Marangoni stress to prevent droplet formation, so that water drains from the surfaces in thin sheets, rather than forming droplets.

The benefits of using it are that it prevents "spotting" on glassware (caused by droplets of water drying and leaving behind dissolved limescale minerals), and can also improve drying performance as there is less water remaining to be dried.

Dishwasher Salt

In some countries, especially those in Europe, dishwashers include a built-in water softener that removes calcium and magnesium ions from the water. Dishwasher salt, which is coarse-grained sodium chloride (table salt), is used to recharge the resin in the built-in ion-exchange system. The coarse grains prevent it from clogging the softener unit; unlike certain types of salt used for culinary purposes, it does not contain added insoluble anticaking agents or magnesium salts. The presence of magnesium salts will defeat the purpose of removing magnesium from the water softener. Anticaking agents may lead to clogging or may contain magnesium. Table salt may contain added iodine in the form of sodium iodide or potassium iodide, but these compounds will not affect the ion-exchange system.

If a dishwasher has a built-in water softener there will be a special compartment inside the dishwasher where the salt is to be added when needed. This salt compartment is separate from the detergent compartment, and generally located at the bottom of the wash cabinet (this is below the bottom basket). On most dishwashers, an automatic sensing system will notify the user when more dishwasher salt is required.

Pouring detergent into the salt compartment will damage the water softening system, however this can be reversed if the user acts very quickly and the dishwasher is NOT used: with a suitable wet and dry vacuum cleaner, remove the foreign substance e.g. detergent, followed by adding water again and removing the water with the wet and dry vacuum and repeating the process several times.

Some dishwasher detergents are marketed for use in hard water areas for dishwashers which do not have a built-in water softener (and therefore do not use any dishwasher salt). These detergents use higher levels of phosphates to increase the solubility of hard water ions. In very hard water areas, the amount of phosphate may still be insufficient and the manual addition of dishwasher salt into the detergent compartment is recommended. Adding salt along with the detergent does not soften the water as does a dishwasher with an ion-exchange water softener, but the water will gain some additional ability to dissolve hard water ions. Note, however, that as water drops remaining on the dishware evaporate, deposits of the salt will likely remain. To combat this, the use of a rinsing agent which cause the water to "sheet" will help eliminate the spotting. Some newer dishwashers allow the use of "all in one" tablets (which include an amount of salt along with detergent and a rinse agent) instead of using separate salt and rinse aid, but dishwasher salt must still be added to the salt compartment in very hard water areas. However, best results are achieved by using separate salt, rinse aid and detergent rather than using the combined "all in one" detergents with these included. Incorrect use of "all in one" tablets/detergents may not be covered under the dishwasher's warranty; it is advisable to check the instruction book when using these types of tablets/detergents.