Yeah, I tried the rice trick during my research. Doesn't actually work very well.
Thing is, rice grows in paddy fields, where it's very wet. And if it readily picked up moisture, we wouldn't have to boil it...
My conclusion was that "rice" works depending on where you put it. Try it in a warm dry environment, and yes "rice" will appear to work. Try it in a cold & damp environment, it won't.
The sodium poly-acrylate, however, just works. You can literally dry stuff out in 24 hours - in a fridge at 5C.