Have you ever drunk birch water?
No. But I love birch beer.
Never heard of it
A couple nights ago, family and I ate at a Russian restaurant in Germany. We tipped gratuitously, which Germans are not accustomed to. The waiter was so pleased with us that he gave us two liters of "birch water" as a gift.
It's kind of sweet & good.
Maybe birch sap?
I hadn't thought of that. That's quite possible.
When we were in Europe last summer, I learned that tipping is not the custom, as it is here.
What is it?
See my story above. I expected to be bitter and tree-like, but it's pretty sweet with only hints of tree. Pretty good.