To make , sea salt is packed into bamboo canisters and sealed with yellow clay. The mixture is baked in an iron oven and roasted in a pine fire.
A bamboo stem is filled with bay salt produced from Korea's west coast, sealed with red clay, and baked in a kiln with pine tree firewood. The baked salt lumps harden after baking. It is taken out, crushed, and repacked in the bamboo stem for the next cycle. During baking the salt absorbs the bamboo constituents that bring a distinctive sweetness, which is called Gamrojung flavor. Baking darkens the salt. The ninth baking process uses the highest temperature, over . Afterwards, the bamboo salt contains blue, yellow, red, white and black crystals.
Well-baked bamboo salt, with a temperature above , is called “purple bamboo salt” because of its unique purple color, which indicates the best quality. While the quality of bamboo salt cannot be solely determined by color, its crystal structure and hardiness is definitive.