Has anyone ever tried birch sap as a tonic?
I've tried unfermented birch sap before (I got it at a local Russian supermarket). I was expecting it to taste somewhat like Birch Beer. Instead, it was surprisingly tasteless; like maple, I suspect one would have to reduce/concentrate it quite significantly to get a pronounced birch flavor. It had the taste and consistency of a thin/diluted simple syrup with only a faint hint of birch flavor.

I made a cocktail using birch sap and ROOT: a liquor modeled after a pre-temperance liquor called "root tea" that was the predecessor to root beer (which is, ironically, non-alcoholic), one of whose primary flavorings is birch bark. I forget what else (if anything) I put in it, but I seem to recall that it worked quite well.

I asked a Russian friend of mine if he had ever heard of fermented birch sap.  He said that, although birch sap ("берёзовый сок", if you ever want to find it in a Russian store) is very popular in Russia, he has never heard of anyone fermenting it.  However, he did add that "Russians would ferment anything…"

On a somewhat related note (at the risk of going off topic), there is an extremely popular low-alcohol drink in Russia called kvas (квас) which is made from fermented rye bread.  Despite the fact that birch sap is also popular, every Russian for whom I've served root beer or birch beer absolutely hates the stuff.  Likewise, I love root/birch beer, however, I hated kvas the first time I tried it (but I have since developed a taste for it, over time).  I have developed this theory:


  Anyone who liked the taste of kvas the first time he/she tried it will undoubtedly dislike the taste of root/birch beer the first time he/she tries it.  Likewise, Anyone who liked the taste of root/birch beer the first time he/she tried it will undoubtedly dislike the taste of kvas the first time he/she tries it.


I have surveyed dozens of Eastern Europeans and Americans alike who have tried both, and I have yet to find a single person that invalidates my theory.  Is there anyone out there who has tried both?