The tradition of storing vegetables harvested in autumn to eat throughout the winter is an ancient practice on the Korean peninsula that can be traced back to the Neolithic era when agriculture began. When buried in the ground for storage, the portions of vegetables that contain moisture would retain their freshness within even as the outer portions dried up. However, this method had the drawback of rendering large portions of the vegetable inedible. This led to the method of drying vegetables under the shade for prolonged storage. However, this method could not preserve the original flavor of the vegetables. Generations of trial and error in search for a better method of preservation led to the discovery of pickling in salt water.
This method uses what is known in modern food science as osmotic pressure, which is created by the interaction between organic matter in the vegetables and the salt water. With the invention of soy sauce and soybean paste, they too were used along with salt water to pickle vegetables with osmotic pressure. According to records, people living in the Korean peninsula had been practicing kimjang, or kimchi making, as early as the thirteenth century. Koryo era poet and politician Gyu-bo Lee (1168–1241) wrote that radishes were pickled and stored in soy sauce during the summer, and with salt during the winter.
Other vegetables prepared in the ancient kimjang tradition included cabbages and spring onions. Sun-eui Jeon, court physician to King Sejo (1417–1468), the seventh king of Joseon, recorded recipes for cheongchimchae (radish pickled in salt water), chimbaekchae (cabbage pickled in salt water), and saengchongchimchae (spring onion pickled in salt water in Sangayorok [山家要錄]). The term chimchae (沈菜) refers to preserving vegetables in salt water, and modern linguists believe the word kimchi originates from a modification to this term. Kimjang is thought to have originated from chimjang (沈藏), and therefore kimjang literally means “to store kimchi.” Pickling vegetables in salt water is a widespread culinary tradition all over the world. Pickles, sauerkraut, the Chinese paocai (泡菜) and the Japanese tsukemono (漬物) are examples of other such foods.
Kimjang kimchi entered a whole new phase of evolution in the eighteenth century. The Joseon scholar Seok-mo Hong (1781–1857) recorded in his book, Dongguksesigi (東國歲時記), that Seoul citizens would make kimchi in October using the following ingredients: radish, cabbage, garlic, Sichuan pepper, red peppers, and salt, and store the kimchi in earthen jars. Red peppers, which originated in the American continent, were introduced to the Korean peninsula toward the end of the sixteenth century and naturalized, resulting in a new form of kimchi involving the marinating of salted vegetables in a sauce made of various spices. This new method of pickling meant that less salt could be used while locking in flavors and scents from various spices into the vegetable. Thus, the Korean kimchi became a richly flavored delicacy, going through the various processes of salting, flavoring with spices, and fermentation.
Since the eighteenth century, it has been the tradition for Korean families to gather in late autumn to make red kimchi, watery kimchi (dongchimi), white kimchi, and jang kimchi, storing them in earthen jars that are buried in the ground. This practice is called kimjang. As kimjang involves a large amount of labor, neighbors had to cooperate with each other, leading to the practice of kimjang pumasi (communal labor exchange). With the rapid advance of urbanization and industrialization in the late twentieth century, kimjang has become centered on individual families rather than the community. In 1992, the year when the percentage of Korean population living in multiunit dwellings reached 65 percent, the kimchi refrigerator was invented, which enabled kimchi storage to be moved indoors. There are myriad flavors in the Korean kimjang tradition, with each household having its own recipe. The recipe is handed down from grandmothers to mothers and from mothers to daughters or daughters-in-law. This has ensured the preservation of the core skill of culinary vegetable fermentation to the present day through the practice of kimjang in the social units of families.