SAP PROCESSING

The sugarhouse is where sap becomes syrup.  A fully equipped sugarhouse will have a storage tank, an evaporator, a readily accessible fuel supply, and perhaps modern technologies such as a reverse osmosis, preheating, or vapor compression systems. Other items include facilities to store and package the syrup, and perhaps a kitchen for the production of other products such as maple candy.

You'll see modern evaporators make syrup from sap.
Wood was the traditional fuel for maple syrup production.  Its advantage was its availability from forest management such as removing diseased trees.  Wood also creates an atmosphere that many producers feel is part of the perfect overall experience.  However, most wood-fired evaporators are inefficient compared to those using other types of fuel used by modern evaporators.  It takes one full cord of wood, 128 cubic feet, to produce approximately 25 gallons of syrup.

Sap becomes syrup by evaporating the water from it, so the concentration of sugar increases from about 2% to approximately 66%.  In a modern evaporator, the sap flows first into the "sap pan", where heat is transferred throughout the sap evaporating the water.  Next, the more concentrated sap flows into the "syrup pan", where it is finished into syrup.

Three methods are commonly used to judge when the sugar content is suitable.
In noncommercial operations, the maple producers may use a method known as "sheeting" where a flat edge scoop is dipped into the nearly finished sap and removed. The flat edge will shed the syrup in "sheets" if it has reached the correct sugar concentration.  However, commercial operations require greater quality control and rely on hydrometers or refractometers, which use physics principles to accurately measure sugar concentration.

Maple producers use several different types of evaporators
Because it is difficult to process sap to syrup completely in the evaporator, many maple producers use a finishing pan for the final evaporation of sap to syrup. The finishing pan is typically an open-topped large pan heated from beneath.  It permits a controlled removal of syrup as it reaches the final stages of processing, allowing for removal of higher-grade, more uniform syrup, rather than a batch removal from the evaporator.

Commercial producers often store syrup in 30-gallon drums during the production season as packaging in the smaller containers would take precious time away from the evaporator and related demands. Syrup in drums can be sold in bulk to various outlets or repackaged by the producer into smaller containers.

Before syrup is packaged, it must be filtered to remove precipitates that form during processing.  After filtering, syrup is graded according to the amount of light passing through it.