Combine 1 gallon of water with the malt flour. Remove the particles of floating malt using a fine-mesh strainer, or by cupping it with your hand, and discard. Allow the malt to soak in the water until the water gets cloudy, 5 to 6 hours. Use a fine-mesh strainer to separate the malt flour from the water. Save the cloudy water to make the drink but discard the malt.
Using a rice cooker, combine rice with 3/4 cup of water and cook. After 25 to 30 minutes, the rice should be cooked.
Gently pour the malt water into the rice cooker with the cooked rice. If there are any more floating particles of malt, discard them. Stir 2 tablespoons of sugar into the malt water and rice in the rice cooker. Leave the contents on "warm" for 5 hours in the rice cooker. By now the body of the rice grain should be dissolved and the rice bits should appear in flat pieces.
Transfer the contents in the rice cooker to a pot and boil once with the rest of the sugar mixed in. Chill. Garnish with pine nuts before serving.