【Reading】すなぬき

【English Name】Sand purging

Sand-purging (sunanuki) is the preparatory step of removing sand and mud remaining inside bivalves—such as asari clams, hamaguri clams, and shijimi clams. By soaking them in salt water of roughly seawater strength and using the shellfish's own respiration to make them naturally expel foreign matter, it is an indispensable basic technique in shellfish work in sushi and Japanese cuisine.

The procedure first involves making a salt solution at about 3% salinity (roughly 30 g of salt per 1 L of water). Spread the shellfish in a tray so they do not overlap, submerge them, and cover with aluminum foil or newspaper to block light. Blocking light makes the shellfish more active and promotes the expulsion of sand. Leave them in a cool, dark place for several hours to overnight.

In a sushi kitchen, the quality of this process directly affects the finish of nigiri and gunkan. Serving shellfish with insufficient sand removal greatly spoils the eating experience due to grittiness in the mouth. Especially when preparing asari or hamaguri into toppings by simmering in nikiri or sake-steaming, meticulous sand-purging is the crucial step that determines the level of completion.

Even with shellfish labeled "sand-purged" at the store, it is safer to perform a short additional treatment at home.