BALTEZERS, Latvia (Reuters Life!) - Gourmet chef Martins Ritins holds up a jar filled with a crystal clear liquid and says "wow" after taking a sip.
Like many people in Latvia and other northern and eastern European countries, Ritins was sampling some birch tree sap, tapped from a tall silver birch tree in his own back garden.
The sap, which pours out like water from the trees during a few weeks in the early spring, is said to be one of the healthiest and purest drinks, full of minerals that the tree has sucked up from the ground.
"It cleans our system, it is like a detoxicant, it is absolutely pure, you can't get anything purer," said Ritins, who is the best known chef in the Baltic state of Latvia.
"The Latvians don't have a monopoly on this. I know the Finns do it, the Lithuanians do it, the Estonians do it and the north American Indians did it," he added. The drink is also found in Belarus, Poland, Ukraine and Russia.
Other natural foods such as berries and mushrooms are also widely gathered in this part of the world.
In North America, maple syrup is popular. In Alaska, birch syrup, made from birch sap, is also produced.
Ritins has taken the use of birch sap to a new level in his five-star restaurant in downtown Riga, the Latvian capital, but it is a drink which many people appreciate.
Health magazines and newspapers in Latvia often report at this year about the health benefits of the drink and some nutritionists say it can help against all sorts of ailments, including kidney and liver problems and gastritis.
To get the sap, people drill holes in the side of the tree, stick a pipe into the trunk and catch the liquid in a plastic keg, bottle, bucket or glass jar.
Ritins uses an old metal drill to dig into the bark and quickly bores a hole.
Almost immediately, the birch sap starts to pour out freely, running over his hand and down the side of the trunk.
He places a pipe made of birch wood into the hole and stands back to let the liquid pour into a glass jar. It looks and tastes like pure water, but has a slight woody, nutty taste.
The birch sap season lasts from late March, early April for about three or four weeks, until the trees start to bud.
The drink can be found sold at markets or people simply take it home to drink if they drill into a tree in a forest.
Ritins is so fond of birch sap he uses it instead of water in various recipes, including poaching fish and making soups. He also gives it as an aperitif to restaurant guests.
"It is fantastic to see Americans or Germans or Australians, they have never experienced this before, it is astonishing for them," he said.
Reporting by Patrick Lannin, editing by Paul Casciato