Cu Da village has been making soy sauce since its founding more than 400 years ago. In the past, every local household stored several jars of soy sauce to use all year round. Today, soy sauce is made not only for villagers’ own use, but to sell outside the village.
The soy sauce is made from glutinous rice, salt, soybeans, and water. The sauce is more delicious if it is made with rain water. The rice should be ‘Nep cai hoa vang’ – a special variety of sticky rice of high quality and special flavor grown mainly in the northern delta and midland provinces.
Dinh Van Tinh whose family has been engaged in the craft for 5 generations, said “Technically, making soy sauce involves two steps.
Cooked glutinous rice is fermented for several days in an incubation chamber. After 5 or 6 days, the rice koji, resembling soft green-lentil cake, is moved to a salt tank.
That’s the first step, making koji. Second is to make bean sauce. Roasted soybeans are ground, then cooked again, and boiled for an hour before being scooped into basins to cool down, then poured into jars.
Depending on the size of the jars, it takes 15 to 20 days to steep the bean sauce, which is then mixed with the koji. The paste is returned to the jars and dried under the sun as long as possible.”
Making koji, called mốc in Vietnamese, is the most difficult and tedious part of the soy sauce manufacturing process.
Vu Thi Chat, a Cu Da soy sauce maker, said qualified soy sauce should be like a paste.
She noted: “Koji must be dried as long as possible. The bean sauce must be boiled and kept in jars for 10 to 20 days.
Then the sauce can be mixed with the koji to become soy sauce. Delicious soy sauce tastes sweet. It doesn’t depend on how long it takes to steep the mixture.
It takes less time to make soy sauce in the summer and more time in the winter. If you don’t have good technique, it will be impossible to make soy sauce during the winter, when it takes at least a month to make a batch.”
The best time to make soy sauce is between April and August. With a trademark granted by the Intellectual Property Agency, Cu Da soy sauce has found a firm foothold in the market. It is sold in big supermarkets in provinces and cities nationwide and is exported to other Asian countries.
Hanoian Dinh Thanh Tu said “Cu Da soy sauce is different from Ban soy sauce. It is sweeter and tastier.
In the summer, it’s very delicious to eat spinach, pickled eggplant, and braised fish with soy sauce. During the Tet holiday, boiled beef, veal, and pork served with soy sauce are delightful.”
It’s hard to confuse Cu Da soy sauce with soy sauce from other places, thanks to its sweetness and special aroma.