A sweet, faintly herbal cooling tea simmered from a changing mix of cooling botanicals — winter melon, sugarcane, dried longan, corn silk, chrysanthemum, cogon-grass root, pandan — then chilled and ladled from big glass jars at the kerb. It is amber-brown, lightly sweet, and barely 'herbal' at all to a first-time drinker; Vietnamese reach for it the way they reach for water on a hot day, to take the edge off the heat. Recipes are loose and vary stall to stall.
Nước sâm — also called nước mát, 'cooling water' — descends from the Chinese-medicine cooling-tea tradition (the same lineage as Cantonese leung cha) carried into Vietnam and reshaped into a street drink, most at home in the hot, humid south. There is no single recipe or origin point: each vendor blends whatever cooling ingredients are at hand, which is why the jars at one stall taste nothing like the next. The name borrows sâm (ginseng) as shorthand for a restorative tonic, though most versions contain no ginseng at all. As with other cooling drinks, its 'detoxifying, heat-clearing' reputation is folk belief rather than established medicine.
Served ice-cold and clear amber-brown. The taste is gentle and rounded — sweet first, then a quiet vegetal-floral background from whatever went into the pot, with winter melon and dried longan pushing it toward a soft, almost smoky-sweet note and chrysanthemum lending a faint perfume. There is none of the harsh bitterness of a Cantonese 'twenty-four-herb' brew; this is the friendly, drinkable end of the cooling-tea family, closer to a lightly sweetened iced tea than to medicine. Refreshing and clean, with no aftertaste to speak of.
Everything is simmered together in water for an hour or so to draw out colour, sweetness, and aroma, then strained and chilled hard. Winter melon and sugarcane supply most of the natural sweetness and the amber colour; dried longan deepens it; corn silk, cogon-grass root, and pandan add the herbal-cooling background and a green-tea-like fragrance. The brew is made in large batches because it sells fast and does not keep well — left more than a day it sours — which is why it lives in those tall jars over ice and is ladled out cup by cup through the day.
Variations
There is no fixed formula — common builds lean on winter melon (nước sâm bí đao), sugarcane, dried longan, lotus seed, monk fruit, corn silk, cogon-grass root, chrysanthemum, and pandan, in any workable combination. Some southern stalls run a darker, more medicinal 24-herb style closer to the Chinese original; others keep it light and fruity. The winter-melon version is the gentlest and most widely sold; jars are often labelled simply by their headline ingredient.
On the Palate
Where Nuoc Sam sits in the Vietnamese flavor cloud
Ingredients
Serves 6How it's made
6 steps · 15 min active + 1 hour waiting
- 110 min
Rinse the dried and fresh cooling ingredients; peel and chunk the winter melon, crush the sugarcane.
- 25 min
Add everything to a large pot of water and bring to a boil.
- 360 min
Lower to a gentle simmer for about an hour until the water turns amber and fragrant.
Watch outSimmer gently about an hour until the water turns amber and fragrant — that color and aroma mean the sweetness and cooling herbs have drawn out.
- 45 min
Stir in rock sugar to taste and simmer briefly until dissolved.
- 53 min
Strain out all the solids through a sieve.
- 660 min
Chill thoroughly and serve ice-cold over ice from a jar.
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