Have you been washing dirt back onto your laundry? Less could be more when it comes to laundry detergent, experts say. Photo: ANSGAR WERRELMANN
Are we using too much laundry detergent? How much is too much when it comes to getting stains out, and have you been causing dirt to stick around by using too much powder?
The Huffington Post's regular Am I Doing it Wrong? podcast recently talked with 'laundry evangelist' Patric Richardson, who said most people use way too much laundry detergent. The overload results in not all of it being rinsed out, causing dirt and impurities to be stuck back onto our clothes.
Using more than 2 tablespoons a load is counter-productive, Richardson said.
Cutting down on the chemicals for each load could both save us on paying for extra washing powder, but could also be good for the environment.
Dr Jack Chen, senior lecturer at Auckland University of Technology's faculty of Chemistry has reviewed Richardson's advice, and said both the chemistry and the reasoning behind it are solid.
However, he also said it would probably take some adjusting to. Until now he had typically followed the advice on the box: "I think that's usually significantly more than just 2 tablespoons."
"Even for me [2 tablespoons] feels little."
To get the amount right, using powders and liquids rather than pods, allows more control, Chen said.
And: "Also, if you use less, you're also creating less ... environmental pollution, so I think it's always a good idea to use less."
However, Chen said there are likely times we may need more - for a large load, or if the water in your area is hard water.
Hard water is naturally very high in minerals such as calcium (lime), which are mostly dissolved as mineral salts.
"Usually you'd need a bit more detergent to kind of counter the hardness of the water - essentially you're removing the salts from the water that prevent the detergent from working correctly," Chen said.
How does laundry detergent clean our clothes, and why is more counterproductive?
Photo: 123RF
The main ingredients in laundry detergent that makes things clean are the surfactants. Chen describes them as the "workhorses".
"Part of the surfactant sticks to dirt and the other part sticks with water - and it helps pull the dirt away, solubilizes it into water and allows it to wash away.
"The problem is, if you use too much detergent you have too much surfactant in there - what happens is it's really hard then to wash all the detergent away and some of it will hang around. The detergent will have held onto the dirt ... so you get just a little bit of the residual dirt and detergent hanging around [on the clothes]."
So while it is natural to assume the laundry detergent manufacturers' directions on the box have been carefully measured, it is also worth considering that it is in their interest for us to use more, Chen said.
Warm water washes help the cleaning enzymes function, so are preferable, he said. But nowadays, specific cold water laundry powder has specially adapted enzymes that function just as well in cold water.
"So if you're going to use cold water make sure you use the right detergents."
