Combine rice, cinnamon, and 6 cups of water in a container and let sit over night In batches blend rice, cinnamon and water for 2-3 min Strain the blended mixture through a fine mesh strainer into a pitcher. Use a spatula to push the liquid through the strainer. Or strain through a cheesecloth Stir in vanilla and sugar and mix well Add the remaining 4 cups of water and 3 cups of milk and stir Store in refrigerator until cool. Best served with ice.