UNDERSTANDING AUTOMATIC DISHWASHING

Automatic dishwashing is superior to hand dishwashing in other ways. One of the most important of these is the manner in which it sanitizes dishes. A study by the University of Louisville School of Medicine pointed out that the average bacteria count for all machine-washed dishes in their study was less than 1 per plate, while the bacteria count on dishes washed by hand during the same test averaged 390 per plate. Bearing in mind that bacteria are ever present on our hands, on working surfaces, on dishcloths, sponges, dishtowels and the like, it is not surprising that some of the hand-washed dishes in this study had a bacteria count as high as 16,000. All the machine washed dishes easily met the public health standard of 100 bacteria or less per plate, a level recognized by health authorities as safe and attainable.

The benefits of an automatic dishwasher and the specially formulated detergents can only be realized if they are used correctly. It is, therefore, important for the user to understand how the dishwasher works, the purpose of its features and how to load and operate it properly. User's manuals and detergent packages contain this information.

The Dishwasher
The function of the dishwasher is to provide the mechanical action necessary to distribute and direct the detergent solution and rinse waters over, under and around the dishes to loosen and remove soil. The dishwasher must also remove soil-laden waters from the machine after each phase of the cycle and provide for the drying of dishes after the cleaning process has been completed.

Washing Systems
Automatic dishwashers vary in the design of their washing systems (or the means by which water is distributed). Some have a single water source, others may have several water sources. Water is distributed in dishwashers by spray arms or spray towers (or in the case of some older models by an impeller). The design of the spray arms or towers may differ in size, shape and placement in the dishwasher, or in the number, size and location of their water ports (holes through which water is forced). All of the washing systems do a good job, but those with fewer water sources require greater care in loading the dishes to prevent blocking the washing action to various parts of the machine, especially the corners.

The Water
The role of water is to dissolve and carry detergent, wet and loosen soil and effectively rinse the soil away. The velocity with which water is distributed in the dishwasher provides the scrubbing action to loosen and remove soil.

Amount
Cleaning in a dishwasher is accomplished with a relatively small volume of water. Contrary to what some people think, the dishwasher does not fill completely as does a clothes washer. The dishwasher, instead, employs several small fills during a cycle to accomplish the washing and rinsing operations. The total volume of water used in a complete cycle can vary from 6 - 10 gallons, depending on the number of washes and rinses included in that particular cycle.

Water pressure in a home may be noticeably reduced at some times because of numerous household water demands. As a result, insufficient water in the dishwasher could occur. This can be avoided by keeping bathing, laundering and other activities requiring quantities of water to a minimum while the machine is in use.

Temperature
The temperature of the water is an important factor in dissolving detergent, removing food soils and drying dishes properly. To do these things most effectively, the water temperature at the dishwasher should not be lower than 130 degrees F (54.4 degrees C). As temperature is reduced, the removal of greasy and oily soils becomes more difficult; spotting and filming on dishes may occur as well as improper drying.

Hardness
The amount of hardness minerals and other dissolved solids in water present obstacles to good automatic dishwashing results. Hardness minerals can cause spotting and filming on dishware. They must be effectively tied up or sequestered if the results are to be satisfactory. Hardness of water is determined by the amount of calcium and magnesium in the water. It varies from locality to locality and season to season. Water hardness is expressed in grains per gallon (gpg), parts per million (ppm) or milligrams per litre (mg/L)

The Detergent
Automatic dishwashers require detergents with very special characteristics because of the conditions under which the detergent must work. One of its essential characteristics is that it must produce little or no suds or foam because too much foam can inhibit the washing action. Other important functions that a dishwasher detergent should perform are the following:

• Make water wetter (reduce surface tension) to penetrate and loosen soil.
• Tie up water hardness minerals to permit the detergent to do its cleaning job.
• Emulsify greasy or oily soil.
• Suppress foam caused by protein soils such as egg and milk.
• Help water to sheet off surfaces of dishes, thus minimizing water spots.
• Protect china patterns and metals from the corrosive effects of heat and water alone.

SURFACTANT (non-ionic) - lowers the surface tension of water so that it will more quickly wet out the surfaces and the soils. Lowering the surface tension makes the water sheet off dishes and not dry in spots. The surfactant also helps remove and emulsify fatty soils like butter and cooking fat. non-ionic surfactants are used because they have the lowest sudsing characteristics.

BUILDER (complex phosphates) - combines with water hardness minerals (primarily calcium and magnesium) and holds them in solution so that the minerals cannot combine with food soils and so that neither the minerals themselves nor the mineral/food soil combination will leave insoluble spots or film on dishes. A builder helps maintain a desirable level of alkalinity, necessary for good soil removal.

CORROSION INHIBITOR (sodium silicate) - helps protect machine parts, prevent the removal of china patterns and the corrosion of metals such as aluminum.

CHLORINE COMPOUND - aids in sanitizing, helps make protein soils like egg and milk soluble, aids in removing such stains as coffee or tea and lessens spotting of glassware.

SPECIAL ADDITIVES (sodium aluminate, boric oxide, aluminum phosphate, etc.) - may be used to inhibit overglaze and pattern removal from fine china.

ADDITIONAL ALKALIS (sodium carbonate, trisodium phosphate) - may be used to aid in handling greasy food soils.

PERFUME - covers the chemical odour of the base product and stale food odours which might otherwise emanate from the dishwasher.

PROCESSING AIDS - generally inert materials that allow the active ingredients to be combined into a usable form.

A Specially Formulated Product
There are no substitutes for an automatic dishwasher detergent. Only an automatic dishwasher detergent can be used in an automatic dishwasher. These products come in either powder or gel form. All other types of detergents or soaps produce too much suds and will smother the water action necessary for cleaning in the dishwasher. Furthermore, enough suds might be generated to cause a dishwasher to overflow. This could necessitate a service call and could be damaging to the dishwasher and the floor around it. No other type of cleaning product such as baking soda, borax, vinegar or hand dishwashing liquid can be substituted for an automatic dishwasher detergent. These other materials will not perform well and may be damaging to the items being washed or to the dishwasher itself.

Amount
Enough dishwasher detergent must be used to soften the water effectively, suppress foam from food soils, provide the necessary cleaning and suspension of soil and protect materials being washed. Under-use will result in poor cleaning, redeposition of soil, spotting, filming and possibly damage to some items being washed. Both the dishwasher instruction booklet and the detergent package provide guidelines for proper usage. A good general rule is to fill the detergent dispenser cup or cups to the level recommended by the dishwasher manufacturer.

It should be remembered that water hardness in any area may vary from season to season and that more detergent may be needed at some times than is needed at other times.

Packaging
Powder automatic dishwasher detergents readily take up and retain moisture and carbon dioxide gas from the atmosphere. This can cause the product to become lumpy. As long as it properly dissolves it can be used, but may be somewhat less effective. To help prevent this condition, the carton is specially designed to include a moisture barrier. Consumers should open the package as directed, avoiding unnecessary tearing of the outer wrapping and closing the box after each use. Always select undamaged packages and purchase only one or two at a time to ensure maximum product effectiveness.

Storage
Store these products in a cool, dry place. Storage under the sink is not advisable because this area is generally too warm and moist to keep the product in optimum condition.

Rinse Agent
Some dishwashers have automatic rinse agent dispensers which release a liquid wetting agent into the final rinse cycle. Rinse agents in solid form are also available for use in dishwashers without the dispenser. The rinse agent allows the water to sheet off dishes rather than dry in droplets, thus helping to eliminate spotting. It is particularly helpful in hard water areas and when heat is eliminated in the dry cycle to conserve energy.

Safety Tips

• Store automatic dishwasher detergent out of the reach of children, especially toddlers who like to taste and touch everything within their reach.
• Never store automatic dishwasher detergent and other household cleaning products in low cabinets that are accessible to small children. An upper wall cabinet that is within easy reach for convenient use is safer.
• Store all household cleaning products away from food products.
• Keep automatic dishwasher detergent in original container.
• Another child safety measure is to add detergent just before turning on the dishwasher. Return the product to storage shelf immediately.
• On completion of the cycle, check to be sure that no detergent is left in the dispenser cups. Clean out if necessary.
• When discarding containers, be sure they are empty and placed in a covered receptacle.
• Hot water is essential to effective results in automatic dishwashing. To prevent possible burns and scalds, exercise caution, especially with young children, when hot tap water is being used in any area of the home.

Energy Saving Tips

• Load dishwasher correctly for best results.
• Use recommended amount of automatic dishwasher detergent.
• Operate dishwasher only when a full load is accumulated.
• Use shorter cycle if suitable for amount of soil on dishes.
• Eliminate heat during dry cycle if water spotting is not a problem.
• Run the appliance during off-peak hours.

PRODUCTS

DETERGENTS

Automatic dishwasher detergents provide the chemical energy to help remove food soil from all types of cooking and serving items. Unlike hand dishwashing products, these must be very low to non-sudsing. Suds cushion the mechanical cleaning action of the water and result in suds overflow from the machine. In addition, automatic dishwasher detergents should inhibit foam that certain protein-containing foods, such as egg and milk, create. They must also soften water to prevent insoluble deposits, loosen and hold soil in suspension, leave items clean and grease-free so they rinse and dry without spots, and be safe for a wide variety of dishes, glassware, utensils, etc.

Forms

Today's automatic dishwater detergents are available in three forms: powders, gels, and tablets. All forms perform well, so the choice is usually made on personal preference.

Powders are free-flowing granules. Most people are familiar with powders as they are the traditional automatic dishwasher detergent form.

Gels are formulated to provide controlled dispensing. Because of their form, they are less likely to be spilled than powders. Gels dissolve quickly, allowing the detergent to begin working right away.

Tablets are formulated for effective cleaning as well as convenience. Since they are pre-measured, there is no measuring, waste, or mess. One tablet contains the exact dose for a full load. Each tablet may be individually wrapped to protect it from moisture, humidity and to extend its shelf life.

Although tablets are formulated to work in all types of water, you may need to use an extra tablet in extremely hard water.

Depending on their formulation and product form, automatic dishwasher detergents may contain the following ingredients:

Ingredients

Surfactants or surface active agents loosens soil and emulsifies fats, helps hold them in suspension, and leaves surfaces clean and free from spots and film. Specially developed surfactants having the lowest sudsing characteristic are used.

Phosphates tie up water hardness minerals (primarily calcium and magnesium) so the minerals won't interfere with cleaning or deposit on surfaces. Phosphates also help keep food soil particles in suspension after removal from the soiled surfaces and prevent their redeposition.

Chlorine or Oxygen Bleaches are added to help prevent spots by leaving a cleaner surface than would be obtained with either surfactants or phosphates alone. The very small amount of bleach helps break down protein soils and aids in removing stains such as coffee or tea.

A Corrosion Inhibitor, such as sodium silicate, helps provide protection for the dishwasher and the wide variety of materials that are washed. Some materials still should not be washed in the automatic dishwasher. The corrosion inhibitor is also a soil suspending agent and an important source of alkalinity.

Enzymes are naturally occurring proteins that help break down food and soil residue into small particles. The small particles are then washed away.

Special Additives, such as sodium aluminate, boric oxide or aluminum phosphate, may be used to inhibit the removal of overglaze and pattern from fine china. Sometimes antifoams are added to reduce sudsing.

Additional Alkalis, such as sodium carbonate, hydroxide or trisodium phosphate, may be used to aid in handling greasy food soils.

Polymers help prevent film build-up from hard water.

Thickening Agents are used in gel automatic dishwasher detergents so the product remains in the dishwasher cup(s) until automatically dispensed at the appropriate time.

Colourants are added to lend individuality and an appealing appearance to the product.

Processing Aids, generally inert materials, allow the active ingredients to be combined into a usable form.

Fragrance covers the chemical odour of the base product and stale food odours that might come from the dishwasher.

Specialty products are also available to help prevent or correct problems.

SPECIALTY PRODUCTS

Rinse Agents are formulated to lower the surface tension of the water, causing it to sheet off the dishes. A rinse agent helps a dishwasher rinse away residues that cause spots and film. Rinse agents are helpful for obtaining dry dishware when dishwasher energy savings switches are activated, or when dishes are left to air dry.

Liquids are available for use in dishwashers with a built-in rinse reservoir and dispenser. Solid forms are made to attach to the upper dishwasher rack where they slowly dissolve and contribute to each water change in the cycle.

Film Removers are powdered alkaline products containing chlorine and complex phosphates. They can be used to remove build-up of hard water film and cloudiness on dishes and the interior of the dishwasher. The film remover is used in place of an automatic dishwasher detergent in a separate cycle or combined with the dishwasher detergent.

Some dishwasher manuals may suggest the use of white vinegar or citric acid crystals to remove film and stains. When using any product not specifically made for dishwasher use, it is very important to follow the dishwasher manufacturer's instructions precisely and not substitute or vary the procedures. Make certain the product is safe for the item being cleaned.

Lime and Rust Removers are available in liquid or powder form to remove lime and rust deposits from the interior of the dishwasher. The product, a combination of acids, is added at the beginning of the main wash cycle (no dishes or other products should be present) with the dishwasher completing the rest of the cycles automatically. The dishwasher should then be put through another complete cycle using a dishwasher detergent to clean the interior of any dissolved lime or rust residue.

STORAGE

Powder automatic dishwasher detergents tend to pick up moisture and can become caked or lumpy. Moisture can degrade bleaching compounds. This is why most are packaged with moisture barriers or in bottles. Open the package carefully to avoid removing any more of the outer wrapping than is necessary, and always reclose the package tightly. It is wise not to buy any packages that have been slit or torn, or more than one or two at a time to assure freshness and easy pouring. Store in a cool, dry place.

Some gel dishwasher detergents may require shaking before use.

It is important that automatic dishwasher detergent and specialty products, like all household cleaning products, be kept out of the reach of children and inaccessible to them. Storage under the sink may not only make the product too accessible to small children, but it is also too warm and damp for good storage of automatic dishwasher detergents. Do not "store" any detergent in the dishwasher where curious children may find it.

DISPOSAL OF AUTOMATIC DISHWASHING PRODUCTS

Just as you exercise care in the manner in which you use and store other household cleaning products, you should property dispose of empty dishwasher detergent containers or small amounts of leftover products by following some simple procedures.

• Get the most for your money and USE THE PRODUCT UP!

• Always check labels for any special disposal procedures and follow instructions. Unused powder and gel automatic dishwasher detergents, liquid rinse agents, and film and spot removers can be disposed of down the drain. Tablet dishwasher detergents and solid rinse agents can be disposed of in the trash.

• Don't mix products when disposing of them.

• Many communities recycle the plastic containers in which gel automatic dishwasher detergents are packaged. Check local recycling program guidelines and recycle empty containers, when possible.

• NEVER reuse an empty dishwashing product container for another purpose. The label instructions and precautions for one product may be dangerous to someone trying to use those instructions for a different product.

PROCEDURES

WATER TEMPERATURE

For the best cleaning results, be sure water temperature in the dishwasher is hot. Most new dishwashers heat the water right in the tub to compensate for low temperature hot water supplies. If the dishwasher does not have a heat booster, run the hot water at the kitchen sink for a few minutes to clear the line of cool water before turning on the dishwasher.

SCRAPING AND PRERINSING

Pre-rinsing dishes and glassware should not be necessary. An automatic dishwasher detergent and a properly installed and operating dishwasher of reasonably current vintage will do a thorough job with just a scraping off of large food particles. If dishes are loaded into the dishwasher and washed later, the "rinse-hold" cycle can be used; but experience may show that even this is not necessary. Extra heavily soiled cookware may need a rinse, soak or a pre-wash.

LOADING THE DISHWASHER

Variations in dishwashers make it important to study directions and diagrams in the user's manual. The most important factor is the positioning of the dishes and utensils in relation to the wash action.

• Be sure to place the heavily soiled side of each item facing the source of the water spray at the centre of the tub. Don't let large items shield small ones. Place cups, bowls and glasses upside down. Flatware should be loaded according to the manufacturer's instructions.

• Avoid crowding or nesting spoons together so water can reach the soiled areas.

• Place sharp items with points down for safety reasons.

• Be sure more delicate items are firmly supported by the rack so they won't topple and possibly break or chip. Experience and results will show how closely together dishes can be placed and how fully the racks can be loaded for satisfactory results.

• Do not put stainless steel and silver flatware in the same silverware basket compartment. Direct contact between these metals can cause permanent damage to the silver. If possible, avoid placing the basket compartment directly in front of the detergent dispenser cups.

Use only a product made specifically for automatic dishwashers. Any other type will cause oversudsing and possible damage to the dishwasher. Use the amount recommended on the detergent container and in the user's manual, adjusting it to the amount of soil, water hardness and load size. Some detergent dispensers have lines to indicate the amount of detergent to add. In hard water, it is particularly important to use detergent as recommended by the dishwasher manufacturer. In general, the harder the water, the more detergent is required. In soft water, less detergent can be used.

Add the detergent to the dispenser cup(s) after the dishwasher is loaded and is ready to be operated. Be sure the dispenser is dry and clean before adding detergent to maintain optimum performance. This also helps prevent powder detergents from becoming caked in the dispenser. Also, be sure to close the dispenser cup lid. Don't sprinkle or pour detergent on flatware or other metals; spotting and pitting may occur.

SETTING THE CONTROLS

Depending on the model, various cycles are available to the user. They may vary by the number of washes and rinses, type of load, degree of soil, and type of drying (air or heated). For most full loads, the regular or "normal" cycle will do the job well, but consider all the options and use any of the features the dishwasher offers. Special "energy-saving" cycles may be offered. Don't shorten the normal wash time just to save energy; the washing action itself takes very little power. A too-short cycle may be a waste of hot water and detergent if results are poor.

UNLOADING DISHES

When dry and cool, a load of dishes can be left in the dishwasher until needed. Most users agree that unloading should be done before starting to prepare the next meal. To avoid the doubt about "clean or dirty," leave the door latched until all clean dishes are put away. Some newer models have a signal device to indicate the dishwasher has been run.

ITEMS THAT SHOULD NOT GO IN A DISHWASHER

The forceful action, hot water and alkaline detergent in a dishwasher can be harmful to some items. Always check the dishwasher manufacturer's instructions about washing. Here are some items to be considered with caution:

Aluminum utensils: Aluminum, with a coloured or metallic copper or gold look usually on the lids of pans and moulds, has a thin anodized coat that is not dishwasher safe. The harder grey or charcoal-coloured anodic finish applied inside and out to some of the professional type cookware can also be permanently damaged. Plain aluminum will darken when exposed to water, some foods, detergents, and alkaline cleaners such as ammonia or a heated solution of baking soda and water. The degree of discolouration depends partly on the length of contact and metal (some alloys are more resistant). Aluminum can be washed in the dishwasher if the discolouration or the necessity of additional cleaning with steel wool or an acid cleaner is not objectionable.

Cast iron: Do not wash in a dishwasher, as all the seasoning will be removed and rusting will occur.

China (hand-painted or antique): These delicate items should not be washed in the dishwasher. Colour may be removed by the high water temperature and alkaline solution in the dishwasher.

Crystal: Some very fine crystal can break either from sudden exposure to very hot water or from being bumped or toppled.

Cutlery: It is safer to wash kitchen knives by hand since the handles may not be dishwasher safe, and blades can be a hazard in the loading or unloading.

Dirilyte: Gold colour will be removed.

Glasses (decorated): Metal trim and colourful enamel decorations on glassware will often fade in time when washed in a dishwasher. Delicate patterns can be damaged.

Knives (hollow-handled): Older flatware may have glued handles which could be loosened by the heat.

Milk glass: Heat may cause yellowing.

Pewter: Will stain, discolour and pit.

Plastics Many plastics are dishwasher safe and remain more stainfree than when hand washed. There are other types of plastics that are heat-sensitive and may melt and warp. Check care instructions on the plastic item. If in doubt, try one. Some may be labelled "top rack only" to keep them away from the heating element at the bottom of the tub. When the dry cycle is not used, they can usually be dishwasher washed if they are heavy enough to withstand the washing action without moving around in the tub.

Silver: May corrode.

Wooden items, including knife handles, will lose their finish, dry out, crack and warp.

SOLUTIONS TO COMMON AUTOMATIC DISHWASHING PROBLEMS