The theoretically best technique (IMO) is to dump the rice in a tub of water and let it sit for 30+ min. That starts the hydration without wasting heat (thus a faster cook). Then I grab a handfuls and rub the grains together to wash mechanically. I know it’s working because the water gets quite cloudy on every cycle. After dumping and repeating 3—4 times, the water is still a dirty color.
How many times does it take?
If you don’t wash brown rice at all, there is a nasty ring of mud around the pot at the level the rice expands to. If you wash ~4 cycles, there is still a faint ring of mud (or so it seems).
I’m way too lazy to do 10 wash cycles, or whatever is needed. I used to put the rice in a strainer and run it under the faucet for a while. But I think that wastes water and you cannot readily see any indication of when the washing is done.
The other problem: people wash their rice not just to get the mud out but also to get the starches out. I want the starches. I’m not afraid of getting fat.
When people talk about rinsing off starch, that’s for white rice which has been milled, resulting in basically rice endosperm dust on the grains. It’s also not about eating excess starch, it’s about having extra starch in the liquid, which then ends up making the rice sticky.
Personally, most of the time, I don’t care about all my grains being nice and separate, and when I do, I use a modified pasta method. I boil a pot of water, and throw rice in, and when the rice is al-dente, I strain it off, and put it back in the pot. I then stick the pot with the lid on into the oven while I finish cooking whatever else I’m making. During that time, the rice absorbs any remaining water, and the texture is perfect. If you had particularly dusty brown rice, you could just rinse the rice a bit first.
When I do rinse rice, I just put it in my pot with an excess of water, and I stir in around with my fingers. I then pour the water off into a watering jug to reuse the water for my plants. I might do that a couple times. Some rice almost never seems clear if you stir hard (especially if you’ve soaked), cause then I think you basically erode new starch into the water. I don’t really like rinsing in a strainer, cause I’ve never found it to work well.