Horchata de Arroz (Rice Horchata)

1 cup white rice, uncooked
3 cups water
1 cinnamon stick, broken into pieces
1 T vanilla 
1 (14 oz) can sweetened condensed milk
1/2 cup granulated sugar
8 cups water

Soak the rice in 3 cups water for 3-4 hours, or overnight. Pour rice (along with the water) and a cinnamon stick into a blender container and puree until mixture is well combined, 1-2 minutes. 

Using a fine mesh strainer, or a colander lined with several layers of cheesecloth, strain the mixture into a gallon size container. Add vanilla, condensed milk, sugar and 8 cups water. Stir vigorously to blend and refrigerate until well chilled.

Before serving, stir horchata well. Pour horchata over ice and dust with cinnamon.