MAPLE SIRUP PRODUCERS MANUAL 



65 



(1) The Brix Value of the Raw Sap.— For 

 example, only half as much water is evaporated 

 from 3°-Brix sap as from a lV2°-Brix sap to 

 make standard-density sirup. Therefore, other 

 things being equal, it would require only half as 

 much oil to make sirup from 3°-Brix sap as from 

 lV2°-Brix sap. 



(2) Temperature of Sap. — The temperature of 

 the sap as it enters the evaporator must be 

 noted, since a great deal of heat is required just 

 to heat the sap from its storage temperature to 

 its boiling temperature. Therefore, the warmer 

 the sap, the less oil required to heat it to 

 boiling. 



(3) The Brix Value of the Finished Sirup.— AW 

 too often the exact Brix value of the finished 

 sirup is not considered in making efficiency 

 studies. Yet a difference of only a few tenths of 

 1° in Brix value has a pronounced effect on the 

 number of gallons of sap that must be evapo- 

 rated to produce the sirup. 



For cost accounting records, most producers 

 will find that merely to divide the number of 

 gallons of sirup made by the number of gallons 

 of oil burned will give the fuel costs per gallon 

 of sirup. These data should be considered an 

 estimate of the efficiency of the oil-burner in- 

 stallation. 



The cost of fuel oil can be kept low by con- 

 tracting for it through competitive bidding. The 

 heat (B.t.u.'s) produced by one cord of wood is 

 approximately equivalent to that produced by 



175 gallons of oil. The efficiency of wood de- 

 pends on many variables, such as condition of 

 the wood, size of the individual pieces, how it is 

 fired, condition of the fire, and stack height. 



Summary' 



(1) Wood 



(a) Use only well-seasoned dry wood, either 

 cord or slab. 



(b) Keep a steady fire. 



(c) Fire first on one side of the firebox, then 

 on the other. 



(d) Keep the fire doors ojien only long enough 

 to charge the firebox. 



(e) Ojjen the dampers and draft doors only 

 enough to furnish the air for combustion. 



(2) Oil 



(a) Oil is recommended if there is a shortage 

 of labor. 



(b) The firebox and arch must be specially 

 built. 



(c) The cost of fuel for making sirup is ap- 

 proximately the same for oil and wood. 



(3) Increase the capacity of the evaporator 

 through the addition of one or more sap or 

 flue pans. 



(4) Mount the supplemental pans on their indi- 

 vidual arches. 



(5) Hook up the supplemental arches in series 

 with the evaporator. 



(6) Use a finishing pan. 



MAPLE SIRUP 



The characteristics of maple sirup are dis- 

 cussed here so that the development of color 

 and flavor will be better understood. 



(Composition of Sap and Sirup 



Table 8 gives the composition of maple sap 

 and sirup. The analyses in this and later tables 

 are not average values; they are analyses of 

 typical saps and sirups. Usually the sirup and 

 sap have essentially the same composition, ex- 

 cept that on an "as is" basis the constituents of 

 the sirup show a thirtyfcld to fiftyfold increase 

 as a result of concentrating the sap to sirup. 

 The amounts of some of the constituents, when 

 expressed on a dry-weight basis, are less in 



sirup than in sap because of their removal from 

 solution as insoluble sugar sand. 



The different kinds of sugar in maple sap are 

 not numerous (91). Sucrose, the same sugar as 

 in cane sugar, comprises 96 percent of the dry 

 matter of the sap and 99.95 percent of the total 

 sugar (table 9). The other 0.05 percent is com- 

 posed of raffinose together with three unidenti- 

 fied oligosaccharides. Un fermented sap does 

 not contain any simple or hexose sugars. 



The sap contains a relatively large number of 

 nonvolatile organic acids (table 10), even 

 though they account for only a small proportion 

 of the solids (89). The concentration of malic 

 acid is 10 times that of other organic acids. If 



