"It's important to have the right weather," said Park Jeom-sik, 56, toting plastic tubs up a moss-covered slope. "The temperature should drop below freezing at night and then rise to a warm, bright, windless day. If it's rainy, windy or cloudy, the trees won't give." For centuries, southern Korean villagers like Park have been tapping the gorosoe, or tree good for the bones.
Unlike North Americans who collect maple sap to boil down into syrup, Korean villagers and their growing number of customers prefer the sap itself, which they credit with a wide range of health benefits. In this they are not alone. Some people in Japan and northern China drink maple sap, and birch sap has its fans in Russia and other parts of northern Europe. But no one surpasses southern Koreans in their enthusiasm for maple sap, which they can consume in prodigious quantities.
"The right way is to drink 20 litres, or about five gallons at once," said Yeo Manyong, a 72-year-old farmer in Hadong. "That's what we do. And that's what gorosoe lovers from the outside do when they visit our village." But how can you drink the equivalent of more than 50 beer cans of sap at one go? "You and your family or friends get yourselves a room with a heated floor," Yeo said, taking a break under a maple tree in Hadong, 180 miles south of Seoul. "You keep drinking while, lets say, playing cards. Salty snacks like dried fish help because they make you thirsty. The idea is to sweat out all the bad stuff and replace it with sap."
Drinking gorosoe has long been a springtime ritual for villagers in these rugged hills, for whom the rising of the sap in the maples is the first sign of the new season. Some villagers even use the sap, which tastes like vaguely sweet, weak green tea, in place of water in cooking. In the past decade, gorosoe sap has become popular with urban dwellers as well. "I send most of my sap to Seoul," said Park, who harvests 5,000 liters, or 1,320 gallons, of sap in a good year.
Koreans may have been drinking sap as early as a millennium ago, historians say. According to one popular legend, Doseon, a ninth-century Buddhist monk, achieved enlightenment after months of meditating cross-legged under a maple tree near here. When he finally tried to get up, his stiffened legs would not work. The sap from the tree fixed the problem. Hence the name's meaning: it is good for the bones.
Kang Ha-young, a researcher said, "But one thing we have found is that the sap is rich in minerals, such as calcium, and is good, for example, for people with osteoporosis, he said. Somehow, our ancestors knew what they were doing when they named it."The New York Times