Wash the rice thoroughly in lots of water. Drain the water and soak for at least 2 hours in enough fresh water. If you do not have time, you can skip this step.
Later drain off to a colander. Let it rest for a while for the water to drain completely. Transfer the rice to a clean dry cloth.
Spread it evenly and fan dry or air dry for about 2 hrs. Alternately you can sun dry till completely moisture free.
How to make rice rava
Add the rice to a blender or grinder. Run the machine to powder the rice to rava. (The texture should be of semolina).
Transfer this to a sieve/filter and pass the rice rava to remove large grains. This is optional, if you don't have large grains you can skip it.
If using new harvest rice, sieve and separate the flour as it makes your food sticky after cooking. Use only the rava for undrallu and store aside the flour for making chalimidi or for dosas. This must be done to avoid undrallu from becoming sticky. * this step is not required if using aged rice
Make sure the rava is dry fully before you move it to a jar.