Entry in progress—B.P.
Wikipedia: Birch beer
Birch beer is a carbonated soft drink made from herbal extracts, usually from birch bark. It has a taste similar to root beer, with a slightly minty and sharper flavor. Various types of birch beer are available, distinguished by color. The color depends on the species of birch tree from which the sap is extracted (though enhancements via artificial coloring are not uncommon). Popular colors include brown, red, and white (clear), though others are possible. After the sap is collected, it is distilled to make birch oil. The oil is added to the carbonated drink to give it the distinctive flavor. “Black birch” is the most common source of extract.
This drink is most commonly found in the northeast United States, and Newfoundland in Canada.
(Oxford English Dictionary)
birch beer U.S., a beverage of slight alcoholic content prepared with an extract from the birch-tree; also a carbonated soft drink flavoured to resemble this
1883 Wheelman (U.S.) I. 392 We reached Bushkill at 12:30 P.M., stopping—for *birch beer—at odd places.
1933 E. C. GUILLET Early Life in Upper Canada iv. 100 There was..a considerable manufacture of birch beer, a very popular drink among those who did not aspire to social heights.
Knight’s Cyclopaedia of the Industry of All Nations
London: Charles Knight
The sap of the birch is made to yield beer, wine, spirit, vinegar, and sugar, according to the mode of treatment; the tree being tapped to allow the sap to flow or ooze out. Birch beer is made by fermenting the sap with yeast, hot-water, and hops;...
19 May 1870, Port Jervis (NY) Evening Gazette, pg. 4, col. 1:
Birch Beer Item.
Our office was invaded on Tuesday afternoon by Mr. George W. Tuthill, who brought along several bottles of birch beer, which he manufactures. All our boys “indulged,” and so did our drinking editor. George is making an excellent quality of beer, and it is becoming quite a favorite with the public.
9 July 1873, New York (NY) Times, pg. 5, col. 5:
A keg of birch beer exploded on a Jersey City fruit stand, yesterday, doing damage to the amount of $25.
15 May 1878, New Brunswick (NJ) Daily Times, pg. 3, col. 4:
He ate two cents’ worth of dates and drank twelve bottles of birch beer.