How does an evaporator work?
Sap is fed into an evaporator unit and kept at a constant level by a float. Evaporators can be heated by a variety of fuel options, including wood, oil and natural gas. The sap moves up and down channels in the evaporator unit, becoming darker as it becomes more concentrated. It eventually passes to a flat pan, is drawn off and is passed through a filter. The pans have covers on then with stacks to take the steam away through the sugarhouse roof; this leaves the air clean in the building and prevents unwanted materials from falling into the boiling sap. Many evaporators now have a pre-heater steam hood, which raises the temperature of the cold sap from about 35 degrees F to 190 degree F using the steam from the flue pan, saving both time and fuel.
