Why you should know:
Arsenic is a carcinogen and has various other negative health effects; enough to warrant exposure limits in various jurisdictions. A five minute boil-and-discard step before cooking is a simple way to reduce your exposure, especially if you eat a lot of rice.
Details are in the study, linked in the title of this post. Here’s a diagram from the abstract:
You could reduce it to 5-6 minutes more by heating your cooking water during the parboil step, rather than after, so it’s ready to go when the parboil is done. In a kettle or second pan, for example.
You could make it 1 minute (the time it takes to pour out the parboil water and transfer the rice) by also taking 5 minutes off the cooking time, since the rice already spent 5 minutes boiling in the first step.
I’m asian and grew up in Asia cooking rice without a rice cooker. This is how we do it:
If I was to boil the rice for 5 mins and throw the water out, that means I need to boil water first (5-8 mins), throw in the rice and wait 5 minutes, then throw out the water. Only then will I do the above steps. The fresh water needs to boil again (5-8 mins) before I simmer for 40 mins.
Good point on heating the new batch of water while doing the initial boil. I can’t say I’ve ever cooked rice by throwing it into already boiling water though, so we’ll see how it turns out.