The unwinding of the fine silk filaments from the cocoon is called reeling. The cocoons are first ‘cooked’ in very hot water in order to soften the sericin. They are then transferred into basins holding warm water. After soaking, the cocoons are lightly brushed to find the ends of the filaments so that they can be unwound. Although there may be as much as 13,000 feet (4,000 metres) of filament in one cocoon, only about one fifth can be reeled into the continuous filament known as net silk. Depending on the final thickness that is desired, between five and ten cocoons are usually reeled together.
The filaments are drawn upward together through a small hole or guide to form a single strand. To help the sericin hold the filaments together and to remove any water that may be clinging to them, a system of small pulleys is arranged so that a filament is crossed at one point either with itself or with a neighbouring filament. This crossing is known by the French term croisure. The resulting strand of yarn is then wound onto a reel and dried. The wound yarn is called a hank. See Diagram of Croisure.