Regarding Birch Beer, I’ve been just a tad confused.
Apparently, Birch sap is similar to Maple sap and a syrup can be made from it which can be fermented and turned into beer, wine, or spirits. However, the sugar levels in Birch Sap are much lower than that of Maple, so the yield is less per gallon.
So, I was initially confused as regards whether Birch Sap or Birch Bark/Extract was used in Birch or Root Beer.
I think the most important quote below is, “Birch Tar oil is almost identical with Wintergreen oil.” As Wintergreen is often considered a substitute for Sassafras in Root Beer, thus Birch Bark or Birch Bark Extract could also be.
In conclusion, while it is possible that Birch Sap has been used to make beer in the US, it is much more likely that Root Beer calls for Birch Bark or Birch Bark Extract.
EDIT: Final Twist!
It appears Birch Beer/Birch Beer Extract is made from the bark/branches of the American Birch species, Black Birch (Cherry Birch,Sweet Birch), Betula lenta, not the European species White Birch, Betula alba, or Paper Birch, Betula papyrifera. The small twigs of Black Birch are known for their Wintergreen flavor, while Betula alba is more camphorous. Unfortunately, it doesn’t appear that Black Birch Bark is available from any online suppliers I can find.
As noted below, Wintergreen Oil and Sweet Birch Oil are essentially identical chemically, so if you’re using one, you probably don’t need to use the other in your Root Beer, especially since it seems to be pretty impossible to find sweet birch bark available commercially. If you’ve got a Sweet Birch (Betula lenta) in your backyard, give making it from scratch a try and let me know how it works out.
From a Modern Herbal, Circa 1931, Mrs. M. Grieve,
“When the stem of the tree is wounded, a saccharine juice flows out which is susceptible, with yeast, of vinous fermentation. A beer, wine, spirit and vinegar are prepared from it in some parts of Europe. Birch Wine, concocted from this thin, sugary sap of the tree, collected from incisions made in the trees in March, honey, cloves and lemon peel being added and then the whole fermented with yeast, makes a very pleasant cordial, formerly much appreciated. From 16 to 18 gallons of sap may be drawn from one large tree, and a moderate tapping does no harm.”
Birch Bark, Contituents:
“Birch bark only contains about 3 per cent. of tannic acid, but is extensively used for tanning, wherever there are large birch forests, throughout Northern Europe. As it gives a pale colour to the skin, it is used for the preliminary and the final stages of tanning. It contains betulin and betuls camphor.
“The leaves contain betulorentic acid.
“By destructive distillation, the white epidermis of the bark yields an empyreumatic oil, known variously in commerce as oil of Birch Tar, Oleum Rusci, Oleum Betulinum or Dagget. This is a thick, bituminous, brownish-black liquid, with a pungent, balsamic odour. It contains a high percentage of methylsalicylate, and also creosol and guaiacol. The Rectified Oil (Oleum Rusci Rectificatum) is sometimes substituted for oil of Cade.
“Birch Tar oil is almost identical with Wintergreen oil. It is not completely soluble in 95 per cent. acetic acid, nor in aniline, but Turpentine oil dissolves it completely.
Western Medicinal Use:
“Various parts of the tree have been applied to medicinal uses. The young shoots and leaves secrete a resinous substance having acid properties, which, combined with alkalies, is said to be a tonic laxative. The leaves have a peculiar, aromatic, agreeable odour and a bitter taste, and have been employed in the form of infusion (Birch Tea) in gout, rheumatism and dropsy, and recommended as a reliable solvent of stone in the kidneys. With the bark they resolve and resist putrefaction. A decoction of them is good for bathing skin eruptions, and is serviceable in dropsy.
“The oil is astringent, and is mainly employed for its curative effects in skin affections, especially eczema, but is also used for some Internal maladies.
“The inner bark is bitter and astringent, and has been used in intermittent fevers.
“The vernal sap is diuretic.
“Moxa is made from the yellow, fungous excrescences of the wood, which sometimes swell out from the fissures.”
“White birch bark was a traditional treatment used by Native Americans in tea and other beverages to treat stomach and intestinal problems that included diarrhea and dysentery.”
“White birch bark contains aspirin-like compounds and should not be used by anyone sensitive to aspirin.”