How Does Your Dishwasher Work?
You own a robot. Despite the Hollywood tradition of depicting robots as anthropomorphic, two legged, humanoid entities, real robots are typically designed for very limited functionality. And appearing human is typically not one of the desired specifications. Your dishwasher is a robot specifically designed to clean your dishes. So how does it work? You probably have a vague idea of warm water and soap being splashed around, but in reality, there is a whole lot going on inside of the modern dishwasher. Dishwashers have improved over time, offering more thorough cleaning, timing and programmable function, and additional safety features.
When you load your dishwasher, avoid nesting items together. This is most easily done by spacing out identical items, such as plates and bowls. If they become nested together, their dirty surfaces will not be exposed.
The first thing a dishwasher does when it is turned on, is it begins heating water. Water has a very high specific heat capacity, which means that it takes a lot of energy to heat it up. This means that your dishwasher will likely have an internal water heater, capable of raising the temperature of your household water to effective levels. Heating the water accomplishes several things. First, heating the water will create a very humid and damp environment. This humidity will cause all surfaces on the interior of the dishwasher to become damp. Saturating food particles and dirt with water can help to loosen the caking of the food. Secondly, hot water can help to sterilize. One vector for disease are small creatures called bacteria. Common bacteria implicated in food borne illnesses are E. Coli, Salmonella, and Listeria. This is why cooking our food before we eat it can protect us from bacteria. Heating the bacteria kills them, rendering them harmless. Therefore, the heating step in the dishwasher helps not only to remove junk, but to kill any harmful microorganisms that might be hiding on your dishes. However, many dishwasher sold to homeowners do not actually heat the water high enough to sterilize the contents. While this is common in commercial dishwashers (so your meal at that restaurant is probably safe), many home models do not yet offer this feature. If it is a feature which is important to you, you may need to shop around to find a model which offers high temperature sterilization. Keep in mind, however, that if you will be heating your dishes to extra high temperatures, you will need to ensure that they are able to stand up to these extreme temperatures. It isn’t helpful if you kill all the bacteria but melt your Tupperware into a puddle. Finally, heating things raises them to a higher energy level. If you remember your high school physics class, particles move around more as they heat up, and can transition from solid to liquid to gas. Heating up your dishes causes the atoms making up the food and dishes to vibrate more rapidly, potentially allowing them to disassociate more easily.
After water is heated, the jets in the dishwasher can begin to spray the hot water and soap across the dishes. Most of the cleaning in the dishwasher is done by high pressure jets of water. These can come from a variety of different surfaces, and each model of dishwasher will have different systems for spraying its contents. When loading the dishwasher, try to orient the dirty surfaces on your dishes so that they are facing the hot water jets. This will allow the water to scour the grime from them more easily, decreasing the likelihood that you later have to wash dishes by hand.
Another important part of dishwasher function is the detergent that you use. Dishwasher detergent carries out three different functions. First, it can serve as a solvent. This dissolves particles, pulling them off of your dishes and into the water which will be washed away. Soaps in general are formulated to try to dissolve particles off of other substance. Secondly, detergent can help to serve as an abrasive. Small particles in the detergent can help to manually rub off grime from your dishes. An extreme example of an abrasive in action is the use of a sandblasting machine, which removes the outer coating from its target. In a detergent, these particles will seek to blast the food particles off of your dishes. Finally, dishwasher detergents must be able to do this without creating too much suds. This is why using dish soap in a dishwasher is not recommended, as it can end up creating so many bubbles that the dishwasher overflows. An overflowing or leaking dishwasher is a huge mess, and could damage both your dishwasher and your home around it. Children (or you) can even be burned through exposure to the superheated water.