A maple syrup producer may need a method for measuring sugar content of their sap/syrup throughout the maple sugaring process. In the past, manual refractometers have been used, but required multiple refractometers due to the wide range of % Brix measured at various stages in the process. There are now digital refractometers that take temperature into account and therefore only one device is necessary.
In the US and Canada, the sugar content of maple syrup must be more than 66% and less than 69%, using the Brix scale. The Brix scale is based on degrees, where 1 degree Brix is equal to 1% sugar. Since all of the dissolved solids in maple sap and syrup is from sugars, Brix is a convenient way to measure sugar content.
A refractometer is another tool to determine when you have syrup.