Sannakji is a traditional South Korean seafood dish based on fresh octopus. The name sannakji derives from the words san (live) and nakji (whiparm octopus or Octopus minor). The octopus species features a smaller body size compared to common octopus (mundeo) or squid (ojingeo). In Korean culinary classification, sannakji belongs to the hoe category, a general term for raw food dishes.
Taxonomically, Octopus minor possesses eight tentacles that are more flexible, with an arm-to-body diameter ratio that is noticeably longer. The muscle tissue of the octopus tends to be more elastic. The raw material for sannakji typically originates from catches in the southern coastal regions of Korea, such as Yeosu, Mokpo, and Buan.
The handling process begins with the removal of internal organs. The ink sac and viscera are discarded first. The octopus body is then cleaned using coarse salt or rice flour to scrape off the mucous layer on the skin surface. A final rinse with ice water is performed to maintain the density of the muscle fibers.
Seasoning Composition in Sannakji Presentation
Sannakji is served with a mixture of sesame oil (gireum-jang), toasted sesame seeds, and salt. Some preparations also include chocang sauce, a mixture of chili paste (gochujang), rice vinegar, and sugar.
Sesame oil serves to reduce the adhesion of the suction cups (acetabulum) on the tentacles. The octopus suction cups operate using negative pressure, which can attach to wet surfaces. The oil layer minimizes the risk of the suction cups adhering to the esophageal wall when swallowed.
The safety of consuming sannakji depends on the cut size and chewing technique. Tentacle pieces that are too long carry a risk of obstructing the airway if the suction cups remain active. Therefore, tentacles are cut into short pieces and must be chewed until the muscle fibers are fully broken down before swallowing.
Why the Tentacles Continue to Move When Served
When sannakji is served, the octopus tentacles can still move despite being severed. The tentacle movement is caused by the octopus’s decentralized nervous system structure. A significant portion of the octopus’s nerve cells or ganglia is located in the arms. It allows the tentacles to respond to stimuli independently of the central brain.
After the body is cut, the cellular tissue in the tentacles still stores reserves of adenosine triphosphate (ATP). The energy reserve triggers independent reflex actions in the tentacle muscles. Muscle movement increases when the tentacles interact with external minerals or chemical compounds.
Sodium chloride in salt and acetic acid in vinegar trigger electrochemical responses in the tentacle nerve cells. The interaction causes faster muscle contractions shortly after the seasoning is poured onto the plate.
Variations in Sannakji Processing Techniques
In addition to standard cutting, there is a processing technique called sannakji tangtangi. The technique involves chopping the octopus on a wooden board using two large knives until the meat is finely minced.
The tangtangi mince is often served alongside other ingredients, such as in the menu item yukhoe-tangtangi. The dish combines minced sannakji with raw beef (yukhoe), sesame oil, and a raw egg yolk.
Another variation is nakji-hoorong. In this style, small-sized octopuses are wrapped whole around wooden chopsticks and coated with seasoning without being cut up. In several coastal regions, the variation is lightly grilled over a low flame to alter the outer texture of the meat without cooking it completely through.
Reference:
Hochner, B. (2012). An embodied view of octopus neurobiology. Current Biology, 22(20), R887–R892. https://doi.org/10.1016/j.cub.2012.09.001
