Alkaline rice dumplings, a distinctive culinary tradition associated with the Tuen Ng Festival, also known as the Dragon Boat Festival, continue to hold cultural and historical significance across southern China and Hong Kong. This year’s festival falls on June 19.

These dumplings, characterized by a springy texture and golden hue, differ notably from the more familiar savory glutinous rice dumplings popular in Hong Kong, which typically include pork, salted egg yolk, mung beans, and mushrooms. Instead, alkaline rice dumplings often feature sweet fillings such as red bean paste or lotus seed paste and are traditionally enjoyed with accompaniments like peanut sauce, honey, or white sugar.

The origins of alkaline rice dumplings trace back to ancient China. Historical documentation indicates that they were first prepared as offerings at altars to deities or ancestors, with methods evolving over millennia. The use of alkaline water—derived from soaking plant ash rich in potassium carbonate and sodium carbonate—dates to the Spring and Autumn Period (circa 770 BC–476 BC) and the Eastern Han dynasty (AD 25–220). This alkaline solution was initially employed for its antibacterial properties and its ability to soften fibers and preserve bamboo shoots before refrigeration technology existed.

By the Jin dynasty (265–420), the practice of soaking glutinous rice in alkaline water gave rise to what became known as alkaline-water zongzi. The method gained particular popularity in southern China among Guangdong, Hakka, and Minnan communities. The alkaline water induces a chemical process known as starch gelatinization, lending the rice dumplings their characteristic golden color, chewy texture, and sticky consistency.

Records from the Ming dynasty (1368–1644) further elaborate on the production of alkaline solutions from plant ash, describing their use not only in dumplings but also in traditional Cantonese mooncakes, where the alkali neutralizes acidity and helps achieve a golden crust, and in bamboo-pressed noodles, which gain a chewy texture and yellow tint.

Historically, these dumplings were vegetarian and commonly offered during rituals honoring gods or the Buddha. Today, commercially produced alkaline rice dumplings often rely on food-grade alkaline water, and the fillings vary, with pure versions eaten simply with sugar, as well as sweeter varieties filled with red bean paste.

Experts emphasize proper preparation techniques—unlike conventional rice dumplings, alkaline versions require looser wrapping to accommodate the rice’s expansion during cooking and prevent bursting or leakage. Some traditional recipes include a red sappanwood stick inserted at the center, which not only imparts a reddish color but also balances the rice’s aroma with that of the alkaline water.

The late Hong Kong food critic Chua Lam praised these traditional alkaline rice dumplings for their soft, smooth texture and subtle flavors, noting that elaborate fillings are not necessary. He particularly admired those from Zhongshan in Guangdong province, which are still made using natural alkaline water prepared from rice straw ash and sappanwood, prized for their fragrance, authentic preparation, and preserved shelf life.

As the Dragon Boat Festival approaches, alkaline rice dumplings remain an enduring symbol of cultural heritage and culinary tradition in southern China and Hong Kong, reflecting centuries-old practices and regional tastes.