Tương Bần (soya sauce) has been a delicacy of northern Việt Nam since the end of the 19th century.

Soya sauce is stored in a large ceramic pot. VNA/VNS Photos Phạm Kiên

Over the past few years, the art of making soya sauce has somewhat declined in Bần Yên Nhân Ward, Hưng Yên Province due to food safety concerns and a decline in quality, because producers are more interested in mass production.

The main ingredient of the sauce is soybean. The soybeans found in Hưng Yên pack a punch and provide the flavour for the sauce.

The other ingredients are sticky rice and salt, while it is fermented in an enzyme known as koji.

Nurturing fungus in boiled sticky rice.

Sticky rice, after being soaked in water and boiled, is spread out on bamboo tray, covered with the leaves of longan or sweet potato.

The boiled rice is left for three days till it turns yellow with the fungus. The leaves are then removed to let the fungus grow freely for one more day.

The fungus is then collected and dried in the sun for two days.

Soybeans are soaked in water and dried before being baked well.

The soybeans are then baked with sand at a low temperature till they turn yellow with a sweet smell.

Then they are soaked again for a week.

Fungus and salt is added, and the mixture is put in ceramic containers, covered tightly and dried in the sun for between two and six months. Experienced soya sauce makers sometimes leave it for up to two years.

The mixture is stirred every two days during the drying period.

During the drying period, makers should stir the mixture every two days, but just for a minute.

The more sunlight it gets, the tastier the sauce is.

Sunlight is an important factor in the process. The more sunlight it gets, the better quality the soya sauce will be.

Hence, from March to August is the main season for making soya sauce.

The final sauce should be a dark brown colour, with a slightly unpleasant odour but sweet taste. The sauce can last for up to three years in good conditions.

Tương Bần is a delicacy found only in Bần Yên Nhân Ward in Mỹ Hào Town, Hưng Yên Province.

As the fungus grows on longan leaves, the soya sauce produced here has a distinct smell and flavour found nowhere else. — VNS