What makes dishwashing detergent work

All detergents — whether intended for hands, hair, clothes or dishes — work on the same principles: Break up oils and dirt and wash them away.

However, different products are formulated for specific conditions and are not interchangeable. The main differences are in the pH, presence or absence of bleach, and the types of surfactants — long molecules that are water-loving at one end and oil-loving at the other. Automatic dishwasher detergents use a brute force approach that is effective but far too harsh for skin, breaking down stains and food with high pH and chlorine bleach.

These two enzymes are called protease and amylase, and they digest protein and starch, respectively.

They break down the food, chopping it into smaller chunks in the same way that the enzymes in your stomach digest food so it can be absorbed and metabolized. Your dishwasher doesn't absorb these nutrients, though: they are flushed away with the rest of the gunk from your dishes.

Firstly, a bit of basic biology. An enzyme is a biological catalyst that makes a chemical reaction happen faster. The starch and proteins in the food stains on your dishes will slowly break down over time, but an enzyme makes it happen much, much faster.

The really smart bit, is that an enzyme is not destroyed or altered in this reaction. Once it has broken down a bit of food, it will float away and start breaking down another bit of food. This means that you only need a very small amount of enzyme to break down a lot of food: each enzyme molecule can break down millions of food molecules. Older detergents used chemicals like phosphates to break the food down, but these chemicals are also broken down in the process, so you need nearly as much phosphate as there are food stains.

Plus, the unused phosphates and other chemicals are washed away and can damage the ecosystem of wherever they end up. Infographics Index. Click to enlarge. Click to enlarge Huge piles of washing up can be daunting — but luckily, dishwashers can make light work of it. This graphic takes a look at some of the key components. Dishwashers use an ion exchange resin to remove calcium and magnesium ions from water.

The ion exchange resin contains sodium ions. As the name suggests, as water passes through it calcium and magnesium ions swap places with sodium ions, softening the water. The supply of sodium ions is finite, so from time to time it needs to be topped up.

This is why you have to add salt to the reservoir in the dishwasher. Adding salt leads to more sodium ions replacing the calcium and magnesium ions, which then wash away. Dishwasher detergents and tablets often containing compounds referred to as builders. These continue to remove calcium and magnesium ions during the washing process. Phosphates, citrates, and polycarbonates bind and remove the calcium and magnesium ions.

The use of phosphate compounds for this purpose has lessened in recent years due to ecological concerns. Namely , they can cause algal blooms in waterways, which can have further impacts on ecosystems. After the water coming into the dishwasher has been softened , dishwashing can begin.