The science of Korean food can be discussed in two broad categories. First, how did Korean cuisine come into being as a food tradition unique to the Korean people? Second, how is Korean food increasingly recognized worldwide as healthy food? Fermentation science plays an indispensable role in the birth of Korean cuisine. The science behind why Korean food has become globally recognized as healthy will be discussed in a future installment.
When asked to discuss the science of Korean food, people typically approach it from two angles. Food and nutrition scholars talk about the cooking processes and nutritional aspects of Korean cuisine. Food engineering specialists discuss only the food science needed for processing and manufacturing. However, the fermentation science discussed in Korean food science contains a deeper story not found in either nutritional or food science.
Korean cuisine cannot be discussed without fermentation, yet academically, Korean food did not give birth to fermentation science. Our ancestors developed Korean food without knowing the concept of fermentation or even the concept of microorganisms. Korean mothers of past generations knew nothing about fermentation or microbes, but they had to feed their children and keep them from going hungry. They needed to make food taste good and accumulated the wisdom to ensure that food eaten later would not cause stomach illness.
That is why it is important to understand Korean food without using terms like fermentation or microorganisms. As previously discussed regarding the development of world cuisines, people needed to eat whatever was available in their given environment without getting sick. Food had to taste good to eat well, and leftover food had to remain edible. The problem of eating grains, including rice, without stomach trouble was largely solved by boiling them over fire. However, boiled rice alone was not enough to eat in large quantities. Side dishes and soups were needed to make rice tasty and easy to swallow. Most side dishes were made using vegetables with seasonings, and occasionally with fish and meat. This is why Korean flavor is called "yangnyeom flavor" or "hand flavor." Korean cuisine developed by finding the optimal path to delicious food within the geographic and agricultural environment of the Korean people.
Yangnyeom, or seasoning, is the core of Korean flavor. The key ingredients for making yangnyeom are aromatic materials such as green onions, garlic, and chili peppers, and the essential sauce is jang (醬, fermented paste and sauce). In other words, seasonings are primarily made from jang. Kimchi also originated from seasoning vegetables with yangnyeom for immediate consumption. When leftovers were eaten days later without causing stomach trouble and instead offered a different, appealing flavor, it evolved into a representative Korean food. When boiled grains or fruits were left for a long time, they developed the smell of alcohol and became makgeolli (traditional rice wine). Some, left even longer, turned into vinegar (醋). Korean ancestors did not discard these. Instead, they used them to develop a culture of eating, drinking, and socializing, giving birth to the unique agricultural culture of the Korean people.
Jang also developed as Korea's unique sauce from this perspective. Soybeans were harvested in autumn, boiled and eaten, or ground into soybean soup. When large quantities of soybeans were boiled in early autumn or warm weather, they would rot and cause stomachaches. But only in early winter or winter could boiled soybeans be left for several days — they would smell, but eating them out of thrift would not cause illness. This is cheonggukjang (fast-fermented soybean paste). In any case, boiled soybeans were edible, but when dried, they hardened. Even when mold grew on them, they did not rot. When these dried blocks, called meju, were dissolved in water, they became edible again. Dissolved in plain water, they would quickly spoil, but when placed in salt water and left for a long time, the hard soybeans softened and became edible. This jang (doenjang, fermented soybean paste) tastes delicious when used to dip chili peppers, garlic, vegetables, or boiled meat. Moreover, in some cases the liquid from this process (ganjang, soy sauce) had an extraordinarily delicious flavor and became primarily used as a dressing sauce for making seasonings. Of course, making tofu and bean sprouts from soybeans is also part of Korea's unique food culture, developed using a form of food science. Because the origin of soybeans is Korea, this soybean food culture exists uniquely in Korea on a global scale.
This is how representative fermented foods — kimchi, jang, alcohol, vinegar, and jeotgal (salted seafood) — were born from Korean side dish culture. The delicious flavors come from the ingredients and seasonings themselves as well as various substances (metabolites) including lactic acid produced during the fermentation process. What prevents food from spoiling is that beneficial microorganisms produced during fermentation fight and overcome harmful, putrefying microorganisms, predominantly occupying the food (以菌制菌, "using microbes to control microbes"). Beneficial microorganisms (lactic acid bacteria) produce many protein-based enzymes that kill harmful bacteria, preventing damage to the body. They produce beneficial, healthy substances that make the food tasty and safe to eat later. When beneficial enzymes are predominantly produced and active, we say the food is "well-ripened" or "well-digested," which is called "fermentation" (醱酵). When harmful enzymes are produced and the food rots, we say it has "gone off" or "decayed," which is called "putrefaction" (腐敗).
Chinese cuisine achieved flavor and preservation through deep-frying in oil. Korean cuisine, however, is the world's only food culture that solved both problems at once — making food delicious and keeping it edible over time — through fermentation.
