NEW YORK (NYTIMES) - There are less daunting methods to beat the summer heat than by wolfing down still-boiling chicken soup for lunch. But followers of a Korean tradition say that few are as effective.

Their mantra is "yi yeol chi yeol", or "fight fire with fire", and their weapon of choice is samgyetang, a whole young chicken or Cornish hen stuffed with glutinous rice, ginseng root, red dates and garlic, served piping hot in its own broth.

At the peak of summer and especially on "sambok", the three days of the year Koreans believe to be the hottest according to the lunar calendar, many of them seek out roiling bowls of samgyetang in the belief that it replenishes nutrients, improves circulation and helps balance the body's internal and external temperatures.

"The concepts that make it good for you on a hot day are rooted in traditional Korean medicine and are very old," said Maangchi Kim, the Korean-Canadian cookbook author and YouTube star. Her video on making samgyetang has been viewed more than 1.4 million times.

The dish predates written records, Kim said, but an early printed recipe for what is now called samgyetang appeared in a 1917 Korean cookbook and called for ginseng powder instead of fresh roots. By the 1960s, refrigeration had made fresh ginseng easier to buy and the practice of eating the soup as a summer tonic, thought to refresh and re-energise, spread widely.

Those wilting under the sun today still turn to it, often instead of chilled foods, as a way to cool down.

"If I have something cold on a hot summer day, I may feel some relief as it goes down," said Kim, who lives in New York City. "But the temperature difference between my body and the environment becomes too large and, after a while, I actually feel hotter than before."

"If I have some hot samgyetang," she added, "I sweat a bit and my body feels more in sync with the environment."

Sceptics might ask for scientific evidence - and be surprised that some exists.

A 2012 study at the University of Ottawa found that drinking warm liquids on hot days can lower body temperature more than drinking cold liquids can because it activates the body's natural cooling system: perspiration. When sweat evaporates, some of the body heat leaves with it, making people feel cooler.

The theory was put to the test on a recent 28 deg C day at Hansol Nutrition Center which, despite its name, is not a shop stocked with vitamins and whey protein, but a Korean restaurant in the Murray Hill section of Queens, known for its samgyetang.

"It's one of the best-selling items on our menu in the summer," said Mr Peter Ro, an owner. "Especially in hot weather."

The dish comes to the table at full boil in an earthenware pot and, as tradition dictates, it is served under-seasoned. Salt is added at the table to the diner's taste: Each pinch helps bring the soup into focus, its richness cut by the sweet red dates and a faintly medicinal tang from the ginseng.

"We very much concentrate on the stock," Mr Ro said. "We try to adhere to the traditional way of preparing it."

He said his recipe is a secret. But samgyetang is almost always made from just a handful of ingredients, with none of the pungent, spicy flavours that Korean cuisine is often known for in the West. The chicken is stuffed with aromatics and simmered until the meat can be pulled easily from the bones with chopsticks.

At Hansol, the soup is silkier than many versions, most likely from an extra helping of starchy rice in the stock. Otherwise, it is typical of the uncomplicated comfort dish that has steamed up Korean kitchens for generations.

Whether it provides relief from the heat ultimately depends on one's definition of relief.

Any cooling effect is not always immediate.

"I guess we're thinking more towards the longer-term benefits," Mr Ro said. "The food you take will have an effect on your health and that makes you feel better."

Kim, though, swears by its tempering qualities. "It might only be psychological for me, as a Korean," she said. "But it feels like it's working."

Samgyetang (Ginseng Chicken Soup)

INGREDIENTS

1/2 cup glutinous (sweet) rice

2 ginseng roots (fresh or dried)

4 small dried red dates (jujubes), pitted

2 Cornish hens, 450g to 600g each

1 tsp coarse kosher salt, more to taste

8 cloves garlic, peeled

4 scallions, white parts sliced, green parts finely chopped

METHOD

1. Rinse the rice, then cover it with water and soak for at least two hours, or overnight. At the same time, soak the ginseng (if using dried; there is no need to soak fresh) and the red dates separately.

2. When rice, dried ginseng and jujubes have finished soaking, drain and rinse them. Remove the giblets from the hens and rub about 1/2 tsp coarse salt all over each, inside the cavity and underneath the skin.

3. Put a couple of spoonfuls of soaked rice into each cavity, then add the ginseng root, jujubes and garlic, and finish stuffing with more rice. Some cooks truss the birds, but the rice will expand during cooking and keep most of the stuffing inside the cavity.

4. Place the two hens and any remaining rice in a pot just big enough to hold them both. Add the white parts of the scallions. Fill the pot with eight cups water or more, if needed, to cover most of the chicken.

5. Cover, bring to a boil, then lower heat and simmer gently for one hour, until the meat falls easily off the bone.

6. Transfer each chicken to a large soup bowl and add the broth. Sprinkle chopped green scallions on top and add salt to taste at the table.

Serves two