When I boil rice, they lump together after a while. How to prevent this?
To get very separate rice I use a long grain rice, pre-rinsed and cooked at a 2 to 1 ratio of water to rice by volume.

There are three factors that affect the tendency for rice to stick together:


Length of the grain. Long grain is the least likely to stick together. Medium and short grain are starchier and are more likely to stick together.
Amount of hydration. If your water to rice ratio is too high, it will cause even long grain rice to cake together.
Cold rinsing. Rinsing your uncooked rice in cold water helps to wash away the excess starch. My basmati rice recipe calls for a rinse followed by soaking the rice in cold water for 30 min to an hour to ensure very fluffy separate rice.