Would the rice eventually absorb all the water and taste pretty much the same as if it had been cooked for 20-30 minutes in boiling water? Let’s assume the water is 75 deg F. Any idea how long “eventually” would be? Then lets assume I left the pot out in the sun for a few hours during a warm summer day.
I don’t know about your scenario, but my rice steamer works by having the rice and water sit in a container on top of the water which gets steamed. As far as I can tell the water with the rice never boils, but is absorbed. I’d guess the absorption rate is proportional to the heat of the water.
I rather think heating the water causes the pot to fill with steam, which exposes all the rice to approxamately the same level of moisture, and that without heating you’d end up with the rice on the bottom being soggy and the rice on the top overly crunchy. On the other hand, perhaps after a few hours normal evaporation trapped by the lid will create the same effect as the steam.
But rice is cheap and its silly to speculate when it’d be easy to find out, so I’ll sacrifice a cup of rice and try leaving it out with a lidded pot and the normal amount of water for a few hours. Will post what happens before I turn in tonight.
Trying to save energy, are we? 
I do not know the chemistry specifics with regard to rice but there’s more to cooking than just absorbing water. Heat changes the chemical structure of certain nutrient components, I think proteins most notably. Rice is mostly starch but starch may be made more palatable in the cooking process as well.
No, just curious. Although I was thinking it might come in handy sometimes when camping.
Good points.
I may just try it one day and see what happens. If I do, I’ll report back.
Well, according to this paper:
Then again, upon reading further, this is directly heating purified starch granules without water.
This paper be useful, but unfortunately my university does not have a subscription, so I can’t access it.
I’m having trouble tracking down the episode, but one time on Dinner: Impossible Robert did not have the equipment availabe to boil rice but he put it in an insulated hotbox, covered it with hot water and left it for a length of time I can’t remember (several hours, I think). It came out (apparently) very edible.
I looked on the Food Network website at the episodes I thought were possible/probable, but of course the recipes they post include cooking the food properly rather than the off-the-cuff method used on the episode itself.
Sorry I can’t give you more than that. It’s a good question, though.