It is interesting
Writer Eugene A. Permyak described the production of sparkling wines “Bersok” from birch sap. Indeed, in 1936 near Sverdlovsk were organized experimental production of birch wines.
In many countries, where birch trees grows (in south-eastern Canada and northeastern United States, especially in the state of Vermont, in Russia, Eastern Europe) people producing syrup by evaporating birch and maple sap.
Birch syrup is lemon-white and thick as honey. It contains 60% sugar.
Nowadays, the famous maple syrup is boiled in Canada. Is used sap of American box elder maple (Acer negundo) and sugar maple (Acer saccharum). Birch sap receive little use for syrup brewing. In the world there is only a dozen of small producers of birch syrup. After all, in order to get one liter of syrup, it is necessary to evaporate 40 liters of maple sap or 100 liters of birch.
In 1946, the Institute of Nutrition of the Academy of Medical Sciences of USSR recommended methods for preparing birch kvass. And in 1968, the Institute of beer-nonalcoholic industry has developed technology to produce kvass from birch sap. In the sap were added sugar, yeast and lactic acid bacteria. After fermentation, the brew cooled, getting rid of the sediment, sweetened and bottled.
In the USSR, a glass of birch sap was worth 8 kopecks (cents). Three-liter jars with birch sap were in almost all stores.
At the end of April, Vsevolozhsk, Leningrad region, hosts the annual Festival of birch sap. The festival demonstrates a birch pipeline connecting 40 birches into a single system and having a flow rate of more than 7 liters per hour.
In the southeast of Canada and birch sap barely produced, maple sap on the contrary, is widely used, mainly for syrup. In Rus birch sap fermented in the large open barrels. Result was a sweet, low-alcohol drink – berezovitsa. Up to X-XI centuries, berezovitsa was the main summer drink, and only later kvass took its place.