Water spinach, known as “rau tiến vua” in Vietnamese, is a popular vegetable in Vietnam that has gained a lot of traction online in recent years, often sold at premium prices.
Water spinach goes by many other names, including “rau cần biển,” “rau cần khô,” and “rau công sôi.” Despite the reference to the sea in some of its names, this vegetable has no connection to the ocean. It is entirely grown on land and is not sourced from the sea like seaweed or algae.
Nowadays, water spinach is typically purchased in its dried form. Before cooking, the dried vegetable is soaked in water to rehydrate it.
Fresh water spinach has soft, pointed, and somewhat tough leaves. It is a herbaceous plant with a cylindrical shape, and mature plants can grow up to 3.3 feet (1 meter) tall.
Water spinach is often confused with fragrant lettuce (“rau diếp thơm” in Vietnamese). While they belong to the same family, they have distinct characteristics.
Water spinach leaves are pointed, while fragrant lettuce leaves are more rounded. Fragrant lettuce leaves are typically harvested for culinary purposes.
The stem of water spinach is a vibrant green and has a crisp texture. People harvest the stems, split them into smaller pieces, and then sun-dry them.
In comparison, the stem of fragrant lettuce is a paler green or even whitish. When placed side by side, water spinach exhibits a more vibrant emerald green color.
The two plants also differ in their growing habits. While fragrant lettuce is adaptable and can thrive in various environments, water spinach is more particular about its growing conditions and is typically grown in coastal provinces.
This vegetable is believed to have originated in Suzhou, Jiangsu Province, China.
It is thought that water spinach first appeared during the Qin Dynasty. However, it was not until the reign of Emperor Qianlong of the Qing Dynasty that this vegetable became a tribute to the imperial court. This is also the reason why it is called “rau tiến vua” or “tribute vegetable.”
Most of us are familiar with water spinach in its dried form. However, this vegetable can also be consumed fresh.
In terms of taste and appearance, water spinach is considered superior to fragrant lettuce, with a crispier texture and more vibrant color.
The high price of water spinach is due to the fact that it takes 7-8 kg of fresh vegetable to produce just 1 kg of the dried product. Water spinach can be used in various dishes, including salads, stir-fries, soups, and pickles.
To prepare water spinach, the leaves are removed, and the outer layer of the stem is peeled. The stem is then split into smaller pieces and sun-dried until completely dehydrated. The dried vegetable shrivels and loses some of its vibrant color, but when soaked in water, it rehydrates and regains its beautiful emerald green hue.
Water spinach is believed to have detoxifying and cooling properties, aiding in digestion and promoting beauty and cardiovascular health. Modern scientific research has revealed that this vegetable is rich in protein and contains over 20 types of essential minerals and amino acids.
Water spinach can be cooked in a variety of ways, but to retain its crisp texture, it is best to cook it briefly. Overcooking will result in a soft and mushy texture. Water spinach is delicious in salads, mixed with chicken feet, pickled with beef tendons, or stir-fried. To prepare, soak the dried vegetable in cold water for about four hours, changing the water once or twice to ensure it is clean and free from any unpleasant odors.
