Wash the rice, then soak it in cold water for at least 8 hours. Drain the rice, and put it in a blender. Have a cup of water from the 2 1/2 quarts standing by. Blend the rice until it turns into a smooth paste. You may need to add the water if it's too thick. Add the rest of the water and the cinnamon stick and put in the fridge for at least two hours. Strain the mix, first through a standard strainer then through wet cheesecloth. Add the sugar and the vanilla, stir until sugar dissolves.