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AGRICULTURE HANDBOOK 134, U.S. DEPT. OF AGRICULTURE 

 Finishing Pan 



Because of the difficulties of finishing the 

 sirup in the evaporator, use of a separate fin- 

 ishing pan is recommended (figs. 80 and 81). A 

 separate finishing pan permits (1) complete re- 

 moval of the almost finished sirup (45° to 60° 

 Brix) from the evaporator, so that there is no 

 possibility of intermixing with less concen- 

 trated sirup; (2) complete control of finishing 

 the sirup without extending the total time the 

 sap is heated; and (3) complete removal of the 

 finished sirup from the pan. 



The size of the finishing pan is determined by 

 the size of the evaporator. Partly finished sirup 

 should be removed ft-om the evaporator at least 

 once each hour and finished in batches. Since 

 sirup transferred to the finishing pan will have 

 a solids concentration of not less than 45° Brix 

 and since it requires 2 gallons of 45°-Brix sirup 

 to yield 1 gallon of 66.0°-Brix (standard-density) 

 sirup, an evaporator that has a rated capacity 

 of 4 gallons of finished sirup per hour requires a 

 finishing pan that holds 8 gallons of 45°-Brix 

 sap and provides additional space to take care 

 of foaming. A pan 18 inches square will hold 

 approximately 1.5 gallons for each inch of 

 depth. Therefore, to accommodate 8 gallons of 

 45°-Brix sap the pan should be 5 inches deep 

 and should have an additional 10 inches for 

 foaming. The pan will therefore be 18 inches 

 square and 15 inches deep. It should have 

 handles and a cover and should be equipped 

 with a precision thermometer having a range of 

 200° to 230° F. in V2° or preferably V4° divisions 

 and a sirup drawoff cock. Preferably, the pan 

 should be heated by gas flame since gas heat 

 can be easily adjusted and can be shut off when 

 the sirup reaches the desired boiling tempera- 

 ture. 



For convenience two finishing pans can be 

 used alternately. When a finishing pan is used, 

 the sap being drawn from the evaporator for 

 transfer to the finishing pan need not be of 

 constant density. It can be any density above 

 45° Brix (3° or more above the boiling point of 

 water). The higher the density of the sirup that 

 is withdrawn from the evaporator, the smaller 

 the amount of liquid that has to be evaporated 

 in the finishing pan. 



Another and important advantage of using a 

 finishing pan is that it permits filtering the 



PN-4776 



Figure 80. — The finishing pan allows complete control 

 over the final stage of the evaporation of sap to sirup. 

 Generally, the fuel is bottled gas. 



sirup that is being transferred from the evapo- 

 rator to the finishing pan. Sirup at this density 

 (45° to 60° Brix) has essentially all of its sugar 

 sand (see p. 78) precipitated. At this density, it 

 has a viscosity (fluidity) only slightly higher 

 than water and filters much more readily than 

 does standard-density sirup. 



In some installations, the sirup is pumped 

 from the finishing pan to the holding or can- 

 ning tank. A cartridge-type filter can be placed 

 in this pipeline to serve as a polishing filter. It 

 will remove any sugar sand that was not re- 

 moved by the major filter or that may have 

 been formed in the finishing pan. 



Many producers using bottled gas to heat the 

 finishing pan report that the cost of fuel is 

 approximately 7 cents per gallon of finished 

 sirup. 



A finishing pan is always used in conjunction 

 with a complete evaporator (flue pan plus flat 

 pan). The flat or sirup pan of the evaporator 

 serves as a semifinishing pan. The capacity of 

 the evaporator is readily expanded by adding 

 one or more flue (sap) pans, each with its own 

 arch and separate heat source (preferably oil). 



