Ahead, we’ll explain how to cook perfect rice in a rice cooker . What is the perfect ratio of water to rice in a rice cooker? How to cook brown rice in a rice cookerThe general ratio brown rice is 1 cup rice to 2 1/4 cups water, using our foolproof method above. How long does it take to cook rice in a rice cooker? After 10 minutes, fluff the rice, layer by layer, with a rice paddle — an essential tool for rice cooker pots that are nonstick.