Birch Sap Sugaring Off
The springtime sugaring off party is a New England tradition. People gather to make pure, chewable candy by pouring thick ropes of boiled-down sugar maple sap onto the snow.
Though sugar maples do not grow in Alaska and Yukon, sugaring off parties are still possible in late April or early May. Then, the sap of birch trees flows upward and makes a reasonable northern substitute for sugar maple sap. The sap from any birch will do.
One of the more common trees in interior Alaska is the paper birch, Betula papyrifera. Easily recognized by its white papery bark, this is but one of three varieties of birch trees in Alaska. These hybridize wherever they meet, so the three birches are considered to be three geographical varieties of a single transcontinental species. Two species of dwarf birch also grow here in the north.
Birch sap contains the sugars glucose and fructose, whereas maple sap contains mostly sucrose. Another difference is that birch sap is more dilute than maple. The birch sap has 0.5 to 2.0% sugar, by weight. To make a thick syrup, the birch sap must be boiled down to decrease its volume by 30 to 40 times, but maple sap needs only 25 times concentration.
The end product is a syrup tasting somewhat like molasses. Birch sap tapped directly from the tree is almost imperceptibly sweet. In Siberia it is bottled with the addition of citric acid and sugar and sold as a good spring tonic.
The easiest way to obtain the sap from a birch tree is to use equipment designed for maple trees. This consists of a spout which is a hollow tube inserted into the tree in a hole drilled about 80 cm (30 inches) from the ground and 1 cm (1/2 inch) in diameter. One centimeter in from the surface of the tree the spout has a 2-3 mm (1/8 in) opening on the bottom side for the sap to flow into the tube from the tree, it then runs out the tube and drips from the end of the spout. Buckets or bags hang from the spout to collect the sap; commercially the sap is piped in plastic tubing under a small amount of suction. It is wise to boil all the equipment to protect the tree from the introduction of fungus and other diseases.
The sap flows for a few days in the spring, when the days are warm and the nights still below freezing. Usually the last two weeks in April is birch sap time around Fairbanks. Some years the sap flow lasts as long as ten days or more, while other years there may be almost no flow at all. At the end of the sap flow, the birch sap turns milky white and becomes bitter to the taste. At this time there are yeasts which appear in the sap which may account for the cloudiness and bitterness. Then the season is ended for another year.
