A Very Ancient Craft
1 gallon birch sap
2 1/2 Ib. sugar
8 oz. raisins
8 oz. citric acid
Birch sap should only be taken from matured silver birch trees, at ]east 6 in. in diameter, during the first two weeks of March, when the sap is rising. Young trees should never be used in case they die after their sap has been used.
Bore a hole slanting upwards about 15in. from the ground and to a depth of 1 in., that is just below the bark. Push one end of a plastic or rubber tube into the hole and the other end into an empty jar, plugging the neck of the jar round the tube with cotton wool. Leave for two or three days until the jar is full, then remove the tube and plug the hole in the tree with a cork. This is most important, else the tree will die.
Boil the birch sap gently for ten minutes, then stir in the sugar and chopped raisins and when cool add the citric acid, nutrient and fermenting yeast. Ferment for five days, then strain and continue fermentation as usual,