What is the solvent in the maple syrup?
Water. Water is the primary ingredient in all sap, including
that of the maple. The syrup is produced by cooking, evaporating,
or otherwise removing most of the water from the sap. Typically it
takes about 40 gallons of sap to make 1 gallon of syrup. Some water
still remains as the solvent in the syrup; removing even more water
will produce a maple candy.