The secret behind the distinctive yellow color of Hoi An's Cao Lau noodles

Cao Lau is the soul of Hoi An cuisine, and what sets it apart from ordinary noodles or rice vermicelli is the natural golden yellow color of the noodles. Many people mistakenly believe this color comes from turmeric or food coloring, but the secret actually lies in three core ingredients: rice, water, and ash water from a specific plant.

First, the rice used for Cao Lau noodles is moderately sticky, not too fluffy. The key highlight is the water – the water used to soak the rice and spread the batter must be clear well water, completely free of alum. Non-alkaline water prevents the batter from turning sour or changing color during light fermentation. The third factor that determines the yellow color is the ash water from a plant that grows in the Hoi An region. The ash is mixed with water, filtered to obtain clear liquid, and then used to soak the rice or mix into the batter. The reaction of this ash water with starch creates the beautiful yellow color, while also giving the noodles a chewy texture and a slight sheen.

The traditional Cao Lau making process requires meticulousness and the experience of the artisan. If any of the three ingredients is missing, the noodles will lose their characteristic yellow color and irreplaceable chewy texture. For visitors to Hoi An, enjoying an authentic bowl of Cao Lau is not just a taste experience but also a way to appreciate the essence of local cuisine through every golden noodle.