I am looking forward to tapping some maple trees later this year for the first time — here is a neat article about the sap itself, which can be used as a healthy beverage or addition to recipes as well as being boiled into sap. Good to know, since it takes 30-40 gallons of sap to make 1 gallon of syrup! I tried some sap about 9 years ago — it was very tasty 
We usually are still burning the wood stove all day in March, tapping season around here, so we’ll do both: boil and drink. Though I don’t see myself drinking 5 gallons in one sitting, you?
In South Korea, Drinks Are on the Maple Tree
By CHOE SANG-HUN
Published: March 5, 2009
HADONG, South Korea — At this time of year, when frogs begin stirring from their winter sleep and woodpeckers drill for newly active insects, villagers climb the hills around here to collect a treasured elixir: sap from the maple tree known as gorosoe.
“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 Mr. 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 an entire mal” — 20 liters, or about 5 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,” Mr. Yeo said, taking a break under a maple tree in Hadong, 180 miles south of Seoul. “You keep drinking while, let’s 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, thanks in part to the bottling industry and marketing campaigns by local governments, gorosoe sap has become popular with urban dwellers as well.
“I send most of my sap to Seoul,” said Mr. 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.
Mr. Yeo said that villagers used to make a V-shaped incision in the tree and insert a large bamboo leaf to run the sap into wooden or earthenware tubs. Then they would carry away the sap-filled tubs on their backs.
Today, villagers usually drill holes in the trees and insert plastic spouts. A maze of plastic tubing carries the sap to holding tanks downhill.
Every year, Hadong produces 317,000 gallons of sap, which fetches between $6 and $7 a gallon. Although most sap harvesters here are tea or persimmon farmers who gather sap on the side for extra income, some enterprising villagers have begun planting thousands of maple trees as a primary business venture.
Some rural governments host gorosoe festivals for tourists, with activities that include sap-drinking contests and rituals venerating mountain spirits. A popular place for drinking sap is public bath houses, where customers take the tonic while relaxing on heated floors.
Promotional pamphlets advertise the sap’s purported benefits: it is good, they say, for everything from stomachaches to high blood pressure and diabetes.
Lee Jae-eung, a naval officer attending the gorosoe festival on Koje, an island east of Hadong, with his two daughters, said he liked the sap because “it soothes my stomach after a hangover.”
Most of these claims have yet to be substantiated, said Kang Ha-young, a researcher at the Korea Forest Research Institute.
“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 seesawing temperatures are needed to collect gorosoe because they build pressure inside the tree, which causes the sap to flow more easily when the trunk is punctured, preferably on its sunny side.
Now that sap-gathering is becoming more commercial, some environmentalists have criticized tree tapping as “cruel.”
“I oppose boring holes in a tree and drinking its sap,” said Kim Jeong-yon, 46, a tourist visiting Koje.
Mr. Kang, the researcher, says careful tapping is harmless. To ensure this, the national forest authorities recently began requiring licenses for sap collectors and regulating the number of holes they can bore into each tree.
Gorosoe farmers, who were doing a brisk business selling sap to visitors from makeshift stands, acknowledged the need for restraint.
“The trees donate their blood to us,” said Yang Heung-do, 51. “If you donate too much blood, you get weak. So we drill only one to three holes per tree, depending on its size.”
