Suribachi is a bowl to grind and mix food. It is an item of cooking equipment to grind food into granules or paste. Inside a suribachi, there are fine combs like threaded dents lined radiately called “kushime (combed line)” for efficiency. Suribachi can be used not only to grind food but also to mix ingredients. When using a small amount of seasonings, most of them stay in kushime, so in order to maximize the flavour, foods are mixed in the suribachi. When making “goma-dofu (sesame tofu)”, white sesame seeds are ground until it forms paste (depends on the amount, but it could take 2 hours), and not to waste remaining sesame paste, shira-ae (vegetables dressed with tofu) is made after grinding sesame seeds. Sesame remaining in the dents are mixed well with tofu and becomes a delicious base for shira-ae. If food is trapped in the dents, it can cause mold to grow, so clean the bowl well with a fine brush and dry well.
Used as a set with suribachi is called surikogi. It’s tip is round and thick, and the handle is slightly thinner than the tip. Materials for surikogi are typically paulownia-wood, magnolia, poplar, Japanese pepper tree and willow, and the best is said to be Japanese pepper tree as it is hard.