Boiling Down – Evaporating
The evaporator is an open pan for boiling water from
the sap. The longer the evaporator and the more deeply channeled the
pan, the more efficient the utilization of heat and the faster the evaporation
process. The faster the sap is changed to syrup or the faster the speed
the sap travels through the evaporator, the better the quality of syrup.
The boiling point of syrup is approximately 7 degrees Fahrenheit above that of water. The boiling point of water varies with the barometric pressure of the day and the altitude. Hundreds of gallons of water in the form of steam are released from the vents of the sugar shack roof each hour. This steam produces low visibility in the sugar shack but does help to keep it warm.
Most evaporators use wood as fuel. Occasionally
oil, coal, or electricity are used. Dry, sound wood is desired because
it produces a hot, steady fire and increases the boiling rate. This wood
is obtained mostly from dead or undesirable types of trees within the
sugar bush itself.
It takes an average of one cord of wood per 17 gallons of syrup. A
cord is a stack of wood 4 feet wide by 4 feet high and 8 feet long.
