Popular colors include brown, red, blue and clear (often called white birch beer), though others are possible.
[9] The oil is added to the carbonated drink to give it the distinctive flavor, reminiscent of wintergreen and methyl salicylate.
Black birch is the most common source of extract in the northeastern region of the United States, where that species is indigenous.
The following recipe is from 1676:[11] To every Gallon whereof, add a pound of refined Sugar, and boil it about a quarter or half an hour; then set it to cool, and add a very little Yeast to it, and it will ferment, and thereby purge itself from that little dross the Liquor and Sugar can yield: then put it in a Barrel, and add thereto a small proportion of Cinnamon and Mace bruised, about half an ounce of both to ten Gallons; then stop it very close, and about a month after bottle it; and in a few days you will have a most delicate brisk Wine of a flavor like unto Rhenish.
Its Spirits are so volatile, that they are apt to break the Bottles, unless placed in a Refrigeratory, and when poured out, it gives a white head in the Glass.