Wash and drain the rice. Place the rice, cinnamon sticks (see note #1 below) and 4 cups of water into a bowl. Cover the bowl and refrigerate overnight (preferably) or a minimum of 4 hours.

Once you'r read to blend the rice, remove most of the cinnamon sticks but it's okay to leave small pieces with the rice.

Blend the rice in two separate batches by adding ½ of the rice & water with some of the cinnamon stick left behind. Puree until it's very smooth and it forms a paste like texture. About 4 minutes long.

Using a very fine strainer (or some cheese cloth) pour the blended mixture over a pitcher. Strain out as much liquid as possible, pushing on the solids with a spatula or spoon.

Repeat this process for the rest of the rice, water & cinnamon mixture

Stir in the milks, vanilla (0ptional), and 4 cups of water. Stir well.

Taste and add more sugar or water if needed.

Chill and stir before serving over ice.