Spouts are then driven into the holes. Some farmers have a pipeline system leading from the trees to storage tanks. Most farmers, however, hang pails on the spouts to collect the dripping sap. The sap may run swiftly or slowly, and the amount of sap produced varies from tree to tree. Maple syrup is made by boiling down the sap.
Constant watch is kept to monitor the syrup's thickness.
Impurities are strained out, and the syrup is canned quickly so that it will not become soured by bacteria. Maple sugar is obtained by boiling down the syrup until enough liquid has evaporated to cause the residue to granulate. Maple sugar and maple syrup are exclusively North American products, simply because the European climate is not conducive to substantial sap running. The United States output comes chiefly from Vermont, New York, Wisconsin, Ohio, Michigan, New Hampshire, Pennsylvania, Massachusetts, and Maine. Most of Canada's production comes from Quebec and Ontario.