Soba noodles are made from buckwheat flour. As buckwheat contains no gluten, wheat flour is usually added to prevent the noodles from falling apart, although 100% buckwheat varieties are available. Soba comes in fresh and dried form, and can be eaten either hot in soup or chilled and served on a bamboo tray called a zaru, with a dipping sauce called mentsuyu. Chilled soba are often garnished with nori seaweed and eaten with wasabi horseradish to add a sharp, pungent flavour.