Patjang is a fermented paste made from adzuki beans (Vigna angularis). It is related to the better-known doenjang, which is made from soybeans, and the production process for both products beings in the same way: In autumn, after the harvest, the beans are soaked, boiled, mashed, and formed into balls or bricks called meju. In the case of patjang, flour (either white or whole wheat) and a few soybeans are incorporated into the paste in order to make it firmer and more savory. The meju are put in a cool, dark place for several weeks to dry, and then moved either outdoors into the sun or to a warm room to ferment until mid winter.
At this point, the processes for patjang and doenjang diverge. The meju for doenjang are submerged in brine inside large earthenware vessels called hangari. To prevent the growth of harmful bacteria, charcoal and chilies are added to the brine. The hangari are stored outside through the winter, and in spring the meju and brine begin to ferment. After a few months the meju are mashed to make doenjang, and the brine is made into ganjang (Korean soy sauce. Because it is so salty, doenjang is often used in soups or as a component of various sauces, though it can also be eaten on its own.
The process for making patjang is much simpler, since the meju are not fermented in brine. Instead, once the initial drying and fermentation phases are complete, the meju are mashed with water and salt and turned back into paste. Patjang is sweeter and more mild that doenjang, and thus often eaten alone. It also makes a nice dipping sauce or a condiment for vegetables.
In the past patjang was a common household product throughout Gyeongsang and Jeolla provinces and was especially important in years when the soybean crop was poor. Today, however, fewer and fewer people make their own sauces and pastes at home, preferring to buy mass-produced versions at the market. From the perspective of commercial producers, patjang is not as attractive as doenjang since its production does not generate an added-value byproduct equivalent to ganjang. Hopefully, shedding new light on the historical importance and gastronomic potential of patjang will renew interest in this traditional specialty.