Homemade Horchata

To a good, strong blender, add the rice, 4 cups of the cold water, the sweetened condensed milk, vanilla, and cinnamon sticks. Cover and blend well for 1-2 minutes or until the rice is broken down into fine grains. Pour the mixture, including the rice and cinnamon, into a large pitcher. Dilute with another 4 cups of water. Mix well. Refrigerate for at least 4 hours until well chilled. The rice and cinnamon will all fall to the bottom of the pitcher. Taste for sweetness - if too sweet, add up to two more cups of cold water until desired sweetness is reached. At this point, it is optional strain the horchata through a fine mesh sieve to remove all of the rice and cinnamon grains and return it to the pitcher before serving (I don't because they stay at the bottom of the pitcher/glass and because authentic horchata usually has some of that still in it. This is a matter of preference.) Serve over ice.