MAPLE SIRUP PRODUCERS MANUAL 



47 



60 90 120 150 



TIME ( MINUTES) 



Chart 8. — The average time (time required to remove 50 

 percent of the water) that any lot of sap remains in the 

 sirup or front pan (see dotted Hnes) is a little more than 

 60 minutes. The time in this pan can also be shortened 

 or lengthened by changing the Brix value of the sap 

 entering the sirup pan, by varying the depth of the sap, 

 and by varying the intensity of the heat. 



must be adjusted to keep the sap proportion- 

 ately deeper. A change in the Brix value of the 

 sap in the supply tank requires a readjustment 

 of the float of the intake valve. Changing to sap 

 with a higher Brix value without readjustment 

 may result in a burned pan. 



Rates of Evaporation 



The solids concentration of the sap is about 

 doubled before it leaves the sap pan, that is, 

 nearly 50 percent of the water that is to be 

 removed has been evaporated {111, 140). By the 

 time the sap reaches a concentration of only 19° 

 Brix, 90 percent of this water has been evapo- 

 rated. 



The changes in the concentration of a typical 

 sap (2.5° Brix) during evaporation are given in 

 table 4. 



A two-section evaporator with three channels 

 in the sap (flue) pan and four in the sirup (front) 



pan and the points at which the concentration 

 was measured (table 4) are shown in chart 9. 

 To make 1 gallon of standard-density sirup 



from this sap required , or 34.4 gallons of 



2.5 

 sap; 33.4 gallons of water had to be evaporated. 

 The solids concentration of the sap was doubled 

 (from 2.5° to 5.0° Brix) in the sap pan. This re- 

 moved 17.3 gallons of water, or more than 52 



Table 4. — Changes in the solids concentration 

 of sap (° Brix) and water evaporated in a 

 simulated evaporator, for each gallon of sirup 

 produced 



' Percentage of sugar. 



- When this experiment was conducted, the Brix of 

 standard sirup was 65.5°. 



^S\ 



Chart 9. — Top view of a simulated maple sap evaporator 

 having 3 channels in the sap pan and 4 channels in the 

 sirup pan. Arrow shows direction of sap flow. The solid 

 circles show the location of sap of different solids 

 concentrations (° Brix), as indicated in table 4. 



