An otoshibuta is used only for Japanese cooking according to wiki. It is a flat lid slightly smaller than the pot’s diameter, so that it drops right on the food while cooking.
Japanese cooking involves a lot of stewing using flavored dashi. To cook condensed flavored stewed vegetable, it is better to use a minimum amount of cooking liquid, in order to prevent the flavor of the ingredients from being thinned out.
A traditional wood otoshibuta can weigh down the ingredients gently, while cooking in a pot, so that the cooking liquid can reach to the top of the food being cooked, and food will not dance around in the liquid. Therefore the food will be cooked evenly without losing the shape. It is particularly useful for stewing soft and starchy vegetables, such as potatoes and kabocha squashes. A wood otoshibuta needs to be soaked in water before each use, so that it won’t absorb cooking liquid and smell. You can buy wood otoshibuta from our store.
A silicone otoshibuta is new, clean, cute, durable, doesn’t absorb smell, and reusable. Due to these advantages, many Japanese home cooks now using silicone type, rather than wood. You can buy from the Japanese-Kitchen store.
Aluminum foil can be used as an otoshibuta as well. Because aluminum foil is disposable (and recyclable), it is convenient to stew fish or other food with strong smell. See the video above for the instruction of how to make an aluminum foil otoshibuta.
My favorite otoshibuta is made of paper. It is disposable like aluminum foil, but the paper also absorbs impurities and unwanted fat which arise during the cooking process. I often use this type of paper otoshibuta when making broth from chicken bones, so that I don’t have to strain the liquid. I bought my paper otoshibuta in Japan, but you can make it easily from paper towel. See the video above for the instruction of how to make a paper otoshibuta.