Rich and Flavorful: The Taste of Lang Bo Fermented Soy Sauce

Made from natural ingredients, Lang Bo fermented soy sauce—a famous specialty of the Dao Xa countryside—boasts an extraordinarily delicious flavor, harmoniously blending the sweetness of soybeans, the aroma of sticky rice, and the rich saltiness of sea salt.

The traditional sauce-making craft in Thach Dong zone contributes to creating a rustic and peaceful countryside picture.

At the local cultural camp within the space of the Hung Kings Temple Festival and Ancestral Land Cultural-Tourism Week 2026, the exhibition and showcase area for the traditional specialty Lang Bo fermented soy sauce welcomed hundreds of delegation visits from all over the country to tour and shop. Ms. Dinh Thi Huong, a tourist from Hanoi, shared: “I knew about Lang Bo fermented soy sauce through online shopping channels and supermarkets. This flavor is my family’s favorite dipping sauce, perfectly suited for boiled dishes like morning glory, pork belly, duck meat, or braised meat and fish. On the occasion of the Hung Kings Temple Festival tour, I visited the booth to both shop and directly learn about the craft of making sauce in its village of origin.”

The local specialty Lang Bo fermented soy sauce is introduced and promoted at the Hung Kings Temple Festival and Ancestral Land Cultural-Tourism Week 2026.

The name “Lang Bo” has long been attached to the Thach Dong area (Dao Xa Commune), a bustling trade zone along the Da River. According to local accounts, fish sauce was very rare in the past, making fermented soy sauce the main seasoning in family meals. After many years during which the craft faded, the Lang Bo Fermented Soy Sauce Cooperative was established with the attention and support of local party committees and authorities. The cooperative built a collective trademark for the product. In consecutive years 2019 and 2020, Lang Bo sauce was certified as a typical provincial rural industrial product and a 3-star OCOP product.

Ms. Tran Thi Phuong, Director of the Lang Bo Fermented Soy Sauce Cooperative, introduced: “The main ingredients of Lang Bo sauce are glutinous rice, soybeans, and salt. Using a traditional family recipe, the people of Lang Bo produce a sauce with a delicious, distinctive flavor—thick and visually appealing with a golden hue. When used for braising fish or meat, the sauce turns an attractive reddish-brown color. When used as a dipping sauce, depending on the dish and taste, other seasonings such as lime, chili, and garlic can be added to create the perfect dip.”

Ms. Tran Thi Phuong, Director of the Lang Bo Fermented Soy Sauce Cooperative, carries out the elaborate sauce-making process.

The process by the people of Lang Bo requires experience and elaborate processing techniques. First, cooked glutinous rice (steamed sticky rice) is incubated to grow mold; the sticky rice is soaked and then cooked into steamed rice. After about a week, it is brought out to dry so the mold dehydrates. Soybeans, after being roasted, are ground into small pieces and soaked in earthenware jars with water for 7–10 days until the beans turn a reddish-yellow color. The soybean liquid is sun-exposed outdoors to become aromatic before being mixed with the dry mold.

According to the Director of the Lang Bo Fermented Soy Sauce Cooperative, the secret to making a delicious batch of sauce lies in selecting the soaking water. The water used to soak the beans must be deep well water from forest veins rather than boiled and cooled water, so that the sauce remains rich and pure. The dry mold is thoroughly mixed with the bean liquid and salt to form the sauce base, which is then carefully fermented for 1–2 months in earthenware jars.

Tourists visit and learn about the sauce-making process at a craftsman household in Thach Dong zone, Dao Xa Commune.

The people of Lang Bo usually make sauce during summer and autumn because of the abundant sunshine and favorable weather. During the fermentation process, sauce makers open the jar lids daily to stir thoroughly and add water. On sunny days, the lids are opened to sun-expose the mixture; on rainy days, the openings are tightly covered with plastic bags to prevent rainwater from entering.

After successfully processing the soy sauce, the product is bottled and labeled for distribution to consumers locally and in provinces and cities nationwide. Since earning brand certification, the Lang Bo Fermented Soy Sauce Cooperative has actively implemented consumption promotion activities and expanded distribution channels through trade fairs, social networking sites, and e-commerce platforms.

Currently, this traditional specialty is available on the shelves of many supermarkets, supplying restaurants and eateries. The cooperative has paid close attention to improving packaging design, contributing to enhancing product reputation and brand recognition.

Today, the traditional sauce-making craft attracts more than 50 households in Thach Dong zone. Beyond helping families increase their income, this handicraft craft contributes to promoting the unique culinary culture of the countryside. It is also one of the craft villages that welcomes tourist groups to experience the manual sauce-making process along their journey to explore eco-tourism and craft village destinations.

Bui Minh