One of the questions I get is whether to use raw rice or cooked rice. I've always used left over cooked rice since that is part of my staple.
Other people have used raw rice and have had their piece blow up, fall apart, or disintegrate during the bisque fire. Why?
Raw rice will pop and puff up like popcorn (it's essentially is puffed rice, like Rice Krispies) during the bisque fire and destroy your piece. Cooked rice will not do that as the outer shell of the rice has been forced open by the cooking process.
Cooked rice is wedged into my paperclay and then my pinch cups/bowls formed from this mixture. The picture shows a recently finished rice bowl - it's literally a rice bowl because of the inclusion. The outside is stained with Iron and Manganese Dioxide. The inside glaze is Celadon. Fired to Cone 10 reduction.