Many people wash their rice before cooking so it does not become sticky (or so they are told). Usually, they do this multiple times until the rice-rinsing water is clear (not cloudy). But does this really have a scientific basis? It turns out you should wash your rice, even if this has no effect on the stickiness of the rice.

A 2018 study by Hongyan Li from the Beijing Technology and Business University compared the effect of washing on the stickiness and hardness of three different types of rice from the same supplier.

The three types were glutinous rice, medium grain rice and jasmine rice. These different rices were either not washed at all, washed three times with water, or washed 10 times with water.

Washing can reduce heavy metal contaminants, such as lead and cadmium, by seven to 20 per cent

The study showed the washing process had no effect on the stickiness (or hardness) of the rice. Instead, the researchers demonstrated the stickiness was not due to the surface starch (amylose), but rather a different starch called amylopectin that is leached out of the rice grain during the cooking process. The amount leached differed between the types of rice grains.

So why should you wash your rice anyway? Traditionally, rice was washed to remove impurities like dust and husks. Moreover, recent concerns about microplastics in rice highlight the value of rinsing. Washing has been shown to remove up to 20 per cent of microplastics present in uncooked rice, a vital consideration in our plastic-laden food supply chain.

Rinsing also aids in eliminating arsenic, a naturally occurring element found in rice. While it removes up to 90 per cent of bio-accessible arsenic, it may also wash away essential nutrients like copper, iron, zinc, and vanadium.

Additionally, studies suggest that washing can reduce heavy metal contaminants, such as lead and cadmium, by seven to 20 per cent.