Long grain white rice (I like Mahatma brand—it’s so inexpensive and GF)
WonderMill Grain Mill (affiliate link)*
*Note about grain mills: There are many, many different grain mills on the market, at many price points. The WonderMill costs a bit more than $200 (U.S.), and is available for free shipping on amazon.com.
I discuss how I researched mills and how I decided upon the WonderMill in the text of this post. You cannot get the same results with even a high-speed blender. I have tried over the years.
The NutriMill (affiliate link) is comparable to the WonderMill in many ways, including price. From reviews, it seems that the NutriMill is louder than the WonderMill during grinding.
Assemble the mill, turn the dial to “pastry” for the finest grind, plug the mill into an outlet, and turn it on by flipping the rocker switch from OFF to ON. While the mill is running, feed your desired amount of dry long grain rice in the hopper of the mill. Allow the machine to run until all of the rice grains have worked through the mill. The WonderMill’s sound will become more high-pitched once it has ground everything. Turn the mill off.
Detach the canister from the mill, tap the top of the container a few times, and open the lid of the container. The only way to grind rice finely in one of these machines is to grind it twice. Transfer all of the ground rice to a separate bowl, and reassemble the now-empty mill. Turn the mill on once again, and place the once-ground rice back into the hopper. The mill will take the already-ground rice in more slowly than it did whole rice grains. Use a utensil to gently push the flour toward the center of the hopper for it to enter the mill, and tap the hopper as necessary to keep the flour moving. Again, the mill will emit a higher-pitched sound when it is finished grinding. Turn off the mill.
Once again, detach the canister from the mill, tap the top of the container a few times, and open the lid of the container. Transfer the finely ground rice flour into a more permanent container with a lid. I like to store homemade ground rice in the refrigerator, as I assume it will go bad more quickly than commercially purchased flour.