I actually tasted this when I was in Latvia. I wasn’t sure what it was and because on my treatment alcohol is strongly advised against I asked and didn’t quite understand it was birch sap till they explained the process. Then I thought: oh like they make maple syrup in Canada but they said not boiled.
It tasted really good and they said it was very healthy for me.
Click here for instructions: Birch Sap (bērzu sula)