Question: Why Do You Need To Rinse Rice Before Cooking It?
By: Helen Pitlick
Published: January 8, 2010

I just bought a rice maker and the directions say to rinse the rice before cooking it. Why is this necessary?

Answers:
Gina Marie Barone

Every type of rice has a starch content. Usually, that starch is to your disadvantage. While the rice cooks the starches begin to caramelize and will burn if not tended to. It's all about manipulation.  You will find that every rice cooker/ gas burner/ electric burner is never consistent with any recipe!! Sushi rice, well, we like some starch to hold it together. But, also will rinse it a few times before cooking. Risotto, arborio rice. very starchy. Has to be prepared methodically, and when prepared properly is creamy and delicious. So, my point being, patience my foodie friend. Trial and error before any dinner party or special occasion. Get a feel for that rice cooker and conquer!
Sheri Wetherell

Washing rice was done back in the day to remove rocks, twigs and other unwanted debris, but today there are many opinions as to whether or not you need to wash your rice prior to cooking. 
Whether to wash or not also depends on where the rice was produced. Most rice produced in the US has been fortified with vitamins and minerals (such as iron), which makes the rice appear powdery. US rice is often labeled as "enriched." If you rinse the rice then you lose these nutrients. Indian rice is not fortified, so washing is good to remove the starch. In Japan, they rinse until the water runs clear and say that doing so helps the rice cook more evenly and taste better.
There are many opinions around whether to wash or not. I generally wash my Asian rices and not my US or brown rices, for what it's worth. 
Here's a great post with more detail: http://british-chinese.blogspot.com/2008/06/rice-to-wash-or-not-to-wash.html
Euclydes Antoni...

Around 90% of the dried polished regular white rice is starch (it may present some variations, but the starch content is usually above 70%).  Although many believe that washing is performed to remove the starch, can you imagine what would you be left with if that was a fact?
The best you can do is remove starch in the form of a rice powder that may accumulate around the grain as a result of the polishing process.
I believe Sheri Wetherel (see above response) is on the right track.
David

Here is an antidote about such reasoning.
For as long as I can remember when baking a ham, my Mother would set the Ham up on the counter and whack off about 5 inches from one side.
I asked her and she said that is how her mother always did it since the time she can remember.
 I asked her mother(Grandma) and she said that is how her mother always did it so she cut off the same amount too.
Finally I asked her mother (Great Grandma) why she always cut off 4-5 inches from the ham and she said that she did it because it would never fit into her one pan if she didn't lop off one side. You can see there is an original reason why we do things even if they do not make any sense to us today, they must have made sense to our forefathers or mothers.
The fact is that many people remember their mom's rice setting in a pan of water soaking before being cooked or saw their mom wash it thoroughly and most likely assumed it was cleaning off some awful germ from a foreign land.
Logically we may have assigned the removal of excess starch to this deed.
Really, what can a splash of water clean that steam won't wipe out? Or boiling wouldn't kill or remove?
steaming for 10 minutes only removes less than half the vitamins and it takes boiling to remove 70 % so a quick rinse will do next to nothing.