Kalua pig is prepared in an Imu.

Traditionally, a fire using koa wood is built in a sand or dirt pit called the Imu. The pit is usually about 6 feet (1.8 m) long, 4 feet (1.2 m) wide and 3 ft (90 cm) deep. Rocks are then placed in the pit to retain cooking heat long after the flames have burned down. Once the rocks have become extremely hot, the hole is lined with traditional vegetation, such as banana leaves. The meat to be cooked is salted, rubbed with herbs, stuffed with more hot rocks, then wrapped with ti and banana leaves. To maintain even heating and to retain the meat's natural moisture, the meat is covered with wet burlap, then with a layer of sand or soil. The meat is then left to cook in the pit for six to seven hours, absorbing smoke and steam from the koa wood and banana leaves. When the meat is fully cooked, it is removed from the Imu and shredded. This is done to allow the melted fat to mix with the meat to help maintain its uniform consistency and flavor.